Although their interactions are initially restricted in Total Drama Island due to being on opposing teams, the vast similarities that Duncan and Gwen share eventually bring them together in a friendship, which is especially prominent later in the series. They become even closer friends in Total Drama Action, which slowly develops into an attraction, despite Gwen denying it at the beginning of the season. Gwen picks Duncan as her first teammate for the Screaming Gaffers and their friendship causes jealousy to rise from their respective romantic partners, Trent and Courtney, leading to tension to arise in their respective relationships.
Around the time Total Drama World Tour starts, Gwen (who had broken up with Trent last season) falls in love with Duncan, but feels very uneasy about it, as Duncan is still dating Courtney. After Duncan quits the competition, Gwen shows signs of missing him and even mistakes a rock formation for him in Newf Kids on the Rock, which Courtney becomes suspicious of. Duncan also shows similar feelings to Gwen and begins to lose interest in Courtney (whom Gwen starts to be friends with) due to her control over him. In I See London..., the two eventually confess their feelings for each other by sharing their first kiss in the confessional. However, Tyler sees it, and Alejandro manipulates Tyler into announcing he saw Gwen and Duncan kiss. An infuriated Courtney breaks up with Duncan in The EX-Files and becomes obsessed with getting Gwen eliminated from the competition. After breaking up with Courtney, Duncan starts a proper relationship with Gwen after sharing their second kiss. However their relationship is put on hold with Gwen's elimination in Picnic at Hanging Dork, and is strained as Duncan's plan to throw Courtney off her game makes Gwen jealous, as she believes that Duncan still has feelings for Courtney. Duncan then becomes guilty of his actions. Alejandro and Heather eventually use Duncan's guilt to get him eliminated. Once Duncan is eliminated from the competition again, he is reunited with Gwen, and the two of them continue their relationship. They are seen making out passionately on a yacht at the beginning of Total Drama Revenge of the Island.
In Total Drama All-Stars, much of their romantic interaction is intentionally subdued by Gwen in order to avoid upsetting Courtney, whom she intends to befriend again. This, in addition to Duncan's constant desire to grab Courtney's attention and make her jealous, leads to the end of their relationship in Moon Madness. Despite this, Duncan isn't hurt or heartbroken, other than being shocked by their sudden break up. A few episodes later, Gwen is finally able to end her feud with Courtney and the newly-reconciled friends spends most of their time mocking Duncan, even when he tries to warn them about a greater evil among the remaining contestants. Duncan leaves the competition on bad terms with Gwen, as she sarcastically mocks him while he is being escorted away by the police after blowing up Chris's cottage.
When Tyler said, "At least you don't have to sleep next to him," Gwen looks intimidated by Duncan, who is seen giving a deer a noogie. Gwen is also impressed when Duncan slices a cockroach in half using an axe.
Gwen and Duncan are the two remaining campers out of the twenty-one who took part in the Awake-a-Thon. After Chris offers a bathroom break, Duncan assures Gwen that he can hold it all day and calls her "sweetheart" (though this may not mean much, as he uses terms of endearment such as this on most girls). Gwen asks Duncan if he could hold it after another ten chapters of a Canadian history book which proves to be too much for Duncan who surrenders and falls asleep in the bathroom.
During the rock climbing challenge, Heather pulls a prank on Gwen that causes her to lose her skirt while climbing the mountain, leaving Gwen with her panties fully viewable to everyone watching the challenge. Duncan is notably seen commenting on the scene and seems very satisfied with what he sees, with Chris agreeing with him.
Even though he isn't close with her at this point, Duncan is angry at Trent for cheating on Gwen by kissing Heather, despite him being framed to look like a cheater. Thus, he agrees to help Leshawna vote off Heather or Trent.
Despite helping her in the previous episode, Gwen decides to help Leshawna and Bridgette to vote Duncan off to avoid allowing the Guys' alliance to become too much of a threat.
Both Duncan and Gwen enjoy the gory movie that the other campers seemed horrified to watch, excluding Izzy. They talk with one another about their favorite gore scenes from other slasher flicks. Heather insults both of them, saying they actually have more in common than "bad fashion sense." Their knowledge in slasher movies allow them to be the final two campers remaining in the contest. Gwen then asks Duncan why he went to Juvie, but he refuses to reveal his personal information. Duncan then manages to trick Gwen into leaving the campfire so that he could face the killer alone and win. Once Duncan rejoins the others after unmasking Chef, he is shown to be greatly concerned when he realizes Gwen is with the real psycho killer. He joins everyone else in rushing to warn her of the danger. He congratulates her with a high five when she successfully fights off the killer.
When Duncan selects a sledgehammer to aid him in capturing a raccoon, Gwen displays doubt over his choice of tools. He takes up her suggestion and instead picks up a chainsaw.
When the final four are trapped on an island, Duncan states in the confessional that it was great to be stuck on an island with two hot girls (referring to Gwen and Heather), before adding they're both "completely insane". After spending the duration of their time on the island arguing, Gwen makes a raft to get herself off the island. However as she had no food, while Duncan had acquired an egg but no ride, the two of them come to an agreement and share a ride together, happily leaving Heather behind. They argue a bit while paddling across the lake, with Duncan insisting that Gwen had no idea where she was going. Duncan turns out to be right when Gwen accidentally paddles back to the same island they just left, only in a different area. Duncan takes his egg back as he runs off from Gwen and the bird, but is soon attacked by the monstrous mother bird (somewhat resembling a Canadian Goose) that wants the egg. After a brief moment where they try to give the egg back to each other, Duncan is captured and carried off by the mother bird. In an attempt to save Duncan, Gwen lassos a nearby rope around the mother bird's ankle to try and anchor it to the ground, but the bird proves to be too strong for her and simply lifts Gwen off the ground instead.
Once they escape and meet up with Heather and Owen, a snake falls out of nowhere, and as they run up into the treehouse, Duncan is seen with his arm behind Gwen's back. The final four hide inside a tree house. At Owen's suggestion they confess their deepest sins, while the sins are never heard by the audience, Gwen is shown shocked at knowing why he was sent to juvie.
After Duncan is eliminated, Gwen tells him that he played the game well, and that she was sorry he had to lose over something as trivial as sticky buns (which was actually Owen's fault). They bump knuckles as a sign of their friendship. Even though they spent most of this episode playing tricks on each other (due to being on different teams), it appears that it was this episode that Duncan and Gwen officially respected each other as contestants and decent people. Gwen was the only one of the three remaining contestants who parted with Duncan on a good note.
Despite becoming friends with him, Gwen did not consider Duncan as one of the sane people, calling Duncan psychotic in the confessional. Duncan was on Owen's side from the beginning rather than Gwen's, even before Owen announced his plans for the party. Also, when Gwen was crossing the beam and the eagle attacked her, Duncan laughed and said that Gwen's near death was awesome TV action, which irritates Courtney. However, Duncan still cheers for her when she announced that she will be throwing a party in Gwen's ending.
Gwen tells Duncan that he is skinny in his own way and tells him that he could use some carbs when he tries to offer Gwen his toast. A jealous Trent grows to hate Duncan, and attempts to fit in with the two by joining in on their conversations about obscure alien movies, to no avail. The two also team-up to take down Mama Alien together with Trent. When Duncan is eliminated, Gwen pokes fun at him for losing and Duncan laughs it off.
When choosing teams, Gwen chooses Duncan first, which upsets Trent and pleases Duncan. After Gwen picks Leshawna and Trent picks Lindsay and Justin, Gwen says, "Oh, pick all the good-looking contestants!" to which Duncan and Leshawna glare at her. Throughout the episode, Gwen and Duncan have positive interactions that border on flirtatious, such as when Duncan catches Gwen when she falls. On the set of the challenge, Gwen motivates Duncan to do the challenge by telling him that he is 'hot, sexy, and stud-like', which disturbs Trent when he overhears. At the end of the episode, Gwen tells Trent not to worry about Duncan, assuring him that Duncan is "no Trent." She also mentions that Duncan still has a picture of Courtney under his pillow, though it is unknown how she would know something so personal, as Duncan is known for being reserved and going out of his way to hide anything that contradicts his rough and tough exterior.
At the beginning of the episode, Duncan laughs after his successful prank in which Trent's saltshaker spills onto his eggs. Gwen then angrily slaps him, calling him a third-grader. Later, at the surfboard balance challenge, the two share a laugh over Harold's rant about his butt. When Duncan wins the challenge for the Screaming Gaffers, they slap fists and hug, which makes Trent call the team a "ticking time bomb of betrayal.” After they return to Camp Wawanakwa, Gwen and Duncan sneak off together during the sand castle challenge in order to take apart the bus they used to get there so they could sleep in the cabins.
Later while Gwen is stressing over Trent's sudden odd behavior and blames herself, Duncan tells her that she is giving herself too much credit. He also points out that Trent's mild insanity over his obsession with the number nine could very well be the fact that the four letters in Gwen's name plus five in Trent's equal nine overall, which horrifies Gwen. While this later turns out to not be the case, Gwen still comes to believe Duncan's word.
Right after everyone (including Duncan) encourages Gwen when she goes to jump onto the horse for the challenge, he says that they'll need a new captain after she jumps. Gwen angrily says that she heard that while getting ready to jump.
While most of the Screaming Gaffers are suspicious of Gwen's behavior (due to her guilt over the nature of Trent's elimination and subtly trying to throw the challenge for her team in this episode), Duncan is one of the few who is not suspicious of her at all and stands up for her. At the end of the episode, Gwen is eliminated, but Duncan is one of the two, along with DJ, who did not vote her off. As she is handcuffed by Chef Hatchet and taken to the Lame-o-sine, Duncan stops them to offer himself in her place, as a way of saying that he really wants to be out of the competition (this may also be interpreted as his standing up for her and sacrificing himself for her), but quickly assures them that he was kidding as soon as Chef attempts to actually take Duncan instead. Gwen tells him that he won't get out of the competition that easily and wishes him good luck. Duncan smiles while he watches her leave.
When the team is talking about the side-deal Gwen had with the Killer Grips, Duncan said he still couldn't believe it and he "didn't know she had it in her," appearing to be more amused or impressed by her actions rather than embittered or betrayed.Geoff told Gwen that her former teammates may not like her anymore, Gwen points out that Duncan didn't vote her off, after which Courtney exclaims that it was only because "she had her goth girl hooks into him." Geoff and Bridgette showed a never-before-seen clip of Gwen and Duncan stargazing. After Gwen made fun of Duncan for openly gushing over Courtney, Duncan compensated with friendly rough housing, which resulted in Duncan accidentally knocking Gwen to the ground, with Duncan soon landing on top of her and he said 'ooh' in a way that may have meant he liked it or that he had won. The two laugh, but then awkwardly pause and stare at each other as the video is paused and no further footage is shown.
It is noted by Geoff that their lips were in very close proximity at the time, as if they were about to kiss at any moment, which enrages Courtney even more. She then says that nothing happened afterward, and that they picked themselves up, stole everyone's underwear and strung it up the flagpole together. This infuriated Courtney, but Gwen insisted that nothing happened and that she and Duncan are still just friends. It is worth something that the anvil did not fall on Gwen after saying this, and it wasn't simply forgotten as Geoff brought the anvil to the audience's attention.
Duncan and Gwen's friendship is brought up again when the recently-returned Courtney, during the prehistoric challenge, accuses Duncan twice of cheating on her with Gwen. Duncan says his relationships are none of her business. Later in a confessional, Duncan says that he never hooked up with Gwen and is still crazy about Courtney.
Right before battling Courtney in the ball pit, Duncan says in the confessional that he knows and feels sorry about what happened to Trent and Gwen, calling it ugly. While in the ball pit, Courtney pins Duncan down and Duncan fears that their relationship would end up being like Trent and Gwen's. Duncan needs to make himself not throw any challenges for Courtney so he repeats "Trent and Gwen...Trent and Gwen...,” not wanting his relationship with Courtney to end the way Trent and Gwen ended.
Duncan reveals that he knows many things about Gwen, including her favorite band, what kind of car she wants, and what kind of guitar her brother has. Unfortunately, he is unable to answer the required question about Gwen; the name of her pet lizards (Angus and Vampyra).
Gwen asks both Duncan and Beth a question on what they would do with the money to help the environment. Duncan says he'd give it to Green Peace, which impresses Gwen. She also most likely voted for him to win, despite saying that she refuses to be predictable.
At the beginning of this special, it shows that Duncan and Courtney break up at the beginning of the episode, and they don't want to even look at each other on the red carpet. During the blogging war between Heather and Gwen, Heather makes a comment dressed in a Gwen wig saying "I wish Duncan was here so I could kiss him, even though I'm too scared to tell him I love him because I'm too cool," showing that Heather is one of the many people who thinks Duncan and Gwen are together. Meanwhile Gwen reveals during one of her blogs that she is getting tons of letters and emails that are asking Gwen if she likes Duncan, that they would make a great couple, and also that she deserves Duncan more than Courtney. Gwen denies it and says that he has a girlfriend, not knowing that Duncan and Courtney already broke up. Then the two hosts of Celebrity Manhunt show her blog after she found out about the break-up. Gwen comments that she couldn't believe that Courtney let a guy like Duncan go, as he was the greatest thing that ever happened to Courtney, but when Gwen tries to explain why, she accidentally reveals that she thinks Duncan is hot. Gwen then nervously retracts this comment and states that Duncan is okay for Courtney. While the contestants are driving to New York, Gwen suggests to Courtney that Duncan should drive the bus, to which Courtney replies that she is not helping. Heather then says that Gwen was just sticking up for her "boyfriend." Later, in the confessional, Courtney says that she'll have to keep a close eye on Gwen in season three, and calls her a "boyfriend stealer."
In the opening sequence, Duncan and Courtney are seen together on a boat, and they crash into something off-screen. When the screen goes back to them, Duncan finds out that he had crashed into Gwen standing in an inflatable raft. Duncan is smiling at Gwen before he realizes she is sinking. While she starts to sink into the water, she looks up at Duncan sadly. Duncan, with a concerned look on his face, immediately leans over to help pull her out of the water, only to stop when he realizes that Courtney is glaring at him from behind. In the section where everyone makes a pyramid, they are seen next to each other.
When they walk off the bus, Gwen makes a snide remark about Heather's "pony hair" hair extensions, which causes Heather to snap back at Gwen that her extensions are made from human hair. Duncan then retaliates that "you learn something new every day,” and Gwen laughs. Gwen looks at him with a friendly smile, and he smirks back flirtatiously (which Courtney does not approve of). Gwen and Duncan were the only contestants that didn't want to sing during Come Fly With Us, until they were convinced by Chris's rules that unless they wanted to be instantly disqualified, all contestants MUST sing in each show. During the pyramid climbing challenge, Duncan suggested that Gwen could use a hand on climbing over the pyramid, something that Courtney wasn't very happy about, but conceded to because, as she put it, "a three-person belay is stronger." While climbing the pyramid, Duncan is annoyed by both Courtney and Gwen, mainly because of their constant bickering. Later, when Chris rings the bell, Duncan is angry, saying that he was tired of listening to Gwen and Courtney's fighting and, after refusing to sing, quits the season, much to Courtney and Gwen's discontent. In a close up, Gwen looked shocked and sad about Duncan's decision.
At the beginning of the episode, Gwen says that she still couldn't believe that Duncan quit the competition and showed some sorrow for his elimination.
In the confessional, Gwen states that being in a relationship with Duncan last season caused her to lose focus in the game. She realizes her slip-up, corrects herself as meaning Trent, but then demands for the confessional tape. Later during the episode, she, along with Courtney, mistake a formation of rocks for Duncan , which Sierra claims only happens if you really really like someone. Courtney says she does, but Gwen denies this in a very nervous way, as if she was lying. This causes her team to lose the boat race.
During their search for "Jack the Ripper" in London, Gwen and Courtney decide to check Whitechapel thinking the final clue leads there due to where The Ripper attacked during his reign of terror. But while The Ripper wasn't found, the duo both found Duncan with his punk band, Der Schnitzel Kickers, performing at a club in the neighborhood, whom they capture and bring back to the show. Back on the plane, when he is first let out of the bag, he doesn't even acknowledge Gwen or Courtney and is angry that they brought him back onto the plane. When they bring him to Chris, Gwen apologizes to him for bringing him back on the plane. After Duncan returns to the competition, he begins hugging Courtney, but smiles romantically at Gwen, who is behind them, as he says "Every time I ran from the cops, I thought of you." Gwen knew that the comment was directed at her and walks away uncomfortably. Later, in the confessional, Gwen tells the audience that she is still confused and "fuzzy" about her feelings towards Duncan and his return. Suddenly, Duncan walks in on Gwen's confessional. Gwen is shocked that she didn't lock the door, but Duncan states that the lock was busted anyway. They then talk a little bit about Gwen's burn on her hand, and how Gwen is "so glad" that Duncan was there to mock her about it. Duncan comes closer, grabbing her hand, and responds that he is too. She then smiles a bit and says "Hey." After a moment of silence, Duncan pulls Gwen in and they end up kissing. Tyler randomly comes in with an astonished look on his face and quickly leaves, shocked at the moment. Afterward, Chris mentions the kiss "as a great way to start a drama" and implies that he was the one who busted the lock on the confessional while a freeze frame of them kissing is still displayed on a small TV in the cockpit.
In the confessional, Gwen notes that she is a horrible person for kissing Duncan right when she had become "friendish" with Courtney and that she should tell her if this happens again. Gwen then happily wonders if it's wrong for her to kiss Duncan again, but she reminds herself that she is a horrible person. In the cafeteria, Duncan and Gwen stare flirtatiously at each other, which Courtney notices. Courtney then pulls Gwen aside and asks why she was staring at Duncan. Gwen, at first stutters, but then responds by saying: "You've really got to do something about that mohawk" which she really did not mean. Courtney believes this and talks to Gwen about what love does to you. While Courtney remains oblivious, Sierra states in the confessional that "Gwen has had a crush on Duncan since season one, and that Duncan has always had some feelings for her too.” She also mentioned that there is a whole fanbase dedicated to "Gwuncan.” They both volunteer for the first part of the challenge, but then try to pull themselves out when they realize who they are competing against. Later, when they both bump into each other, they try to talk about their relationship before Chris forces them to sing a song. Even though Gwen is not required to sing, she does it anyway. During the song, Duncan mentions that he doesn't regret kissing Gwen. Before the tie breaker challenge begins, Gwen starts to worry about Duncan when Chris implies he may not be alive, which makes Courtney feel suspicious. Alejandro, who just discovers her secret, forces Tyler to tell everyone about Gwen and Duncan's kiss. Angered, Courtney orders Cody to stop flying in order for the team to lose so they can vote Gwen off. Cody however, ignores this and wins the challenge. In the confessional, Gwen admits that the kiss was great, but now she and Duncan are at the risk of being eliminated. Fearing Duncan's fate, Gwen sneaks into the elimination ceremony to see who is getting voted off. Although Duncan is supposed to be eliminated, Chris pushes one of the interns out of the plane as he wanted to prolong the current drama. Upon hearing this, Gwen silently cheers for Duncan's safety.
While they were on the plane, Duncan openly flirts with Gwen by saying she looks really pasty and Gwen states that means a lot coming from a cyclops. At the beginning of Boyfriend Kisser, Courtney is shown erasing a drawing of Gwen and her soon-to-be boyfriend, Duncan kissing. Later on in the warehouse when they run into each other, Gwen and Duncan talk about the kiss they shared. She begins to talk about how their kiss was awesome, and then adding that she knows about Courtney's flirting with Tyler getting to him and Gwen asks if he's changing his mind. Then, Duncan cuts her off by kissing her with his lips overlapping her's and popping his leg up romantically. Gwen was initially surprised, but she started to enjoy it and kisses him back.
Gwen tries to remain on her train of thought and tells him, "Why don't we just let things happen?". They both decide to have a normal boyfriend-girlfriend relationship with no plans, pressure or mushy nicknames such as "pookums." Duncan agrees, saying that's the reason why he likes her. When Duncan tries to run back to the challenge, Gwen trips him (in a playful way) and says "try not to get eliminated" and Duncan answers back "same to you" and stares at Gwen in a dreamy, romantic way as she runs off. Gwen yet again sneaks in to the elimination ceremony when Team Chris Is Really Really Really Really Hot loses yet again, to see who goes home. When Chris announces Tyler is going home instead of Duncan, Courtney storms in angrily and kicks Tyler out of the plane while telling everyone that she will have her revenge on Gwen and Duncan.
Alejandro and Duncan had teamed up in order to manipulate Courtney into thinking Duncan was hurt by Alejandro flirting with her. When Heather (who was suspicious of the guys), starts acting nice towards Duncan, Gwen becomes jealous and starts to lose her trust in him. However she is relieved to hear from Heather that there was nothing going on between her and Duncan. When Duncan takes it even further and pretends to cry over Courtney, Gwen's loses her faith again. Gwen ends up being eliminated, and is left with a bad impression about Duncan. Ironically, it was Duncan who lead to Gwen's elimination by throwing the dingo onto Cody, thus both making Team Amazon lose and making Cody too confused to vote against Courtney and leading to the tie-breaker in which Gwen was eliminated. Duncan is aware that he's responsible, and murmurs "crap" when he sees Courtney signaling him with a throat slitting gesture, to tell him Gwen is going home.
Despite Gwen's elimination in the previous episode, Duncan seemed to show very little signs of remorse over her elimination. Upon landing in Sweden, Courtney angrily asks Duncan to apologize for cheating on her with Gwen, to which Duncan calmly replies back "Who?" to further irritate Courtney. At the end of the episode, however, Duncan is seen carving Gwen's face into a chair with his pocket knife, showing that he misses her.
When Cody raises the possibility of Gwen re-entering the competition, Duncan approves the idea by smiling widely and saying "That wouldn't suck." However he is dismayed to discover it's Blaineley.
In this episode, Heather mentioned to Duncan that he caused Gwen's elimination in an attempt to get him off his game, which worked. Duncan glared at Heather and then got tripped by Alejandro. In an exclusive clip, Duncan is excited about his elimination and tells Gwen he'll be seeing her soon though he change it to "later than soon" when he realizes the trouble he is in.
The two of them are seen sitting with each other in the beginning of the episode. When Bruno scared the contestants away from their seats, Duncan appears to be holding Gwen. Other than that, there was hardly any interaction between the two. In the Polish version of this episode, there is an extra scene showing Duncan and Gwen (along with Lindsay and Tyler and Harold and Leshawna) relaxing on the beach together. Courtney is beside them, still rambling on about her hatred towards them. When she starts singing her hate-song to them, Duncan becomes annoyed and throws a sandal at her face. Duncan and Gwen smile at Courtney's plight and smile at each other before sharing a kiss. This indicated that Gwen has forgiven him about the incident several episodes ago.
The two are seen sitting together again at the beginning of the episode. When Duncan makes a comment, Gwen is seen smiling at him.
When the old cast appears on a yacht, Duncan and Gwen are making out passionately while they hold each other.
Duncan and Gwen are seen fighting Courtney towards the end of the intro.
When Gwen is introduced, she is called a "boyfriend stealer" by Chris, referencing Gwen and Duncan's controversial relationship in Total Drama World Tour. As Gwen flies to the ground, she yells that Duncan and Courtney were not dating at the time. When Chris reveals the teams will be split by Heroes and Villains, Gwen sighs in her confessional, thinking she and Duncan won't be on the same team unless Duncan is also a hero. However, they do end up on the same team, the Villains. When Gwen complains about being placed on the Villain team, Duncan tries to calm her down by telling her that being bad is cool. He also reminds her they are both on the same team now. Gwen sighs, still visibly upset about the team selection. Duncan, in a confessional, reveals he only returned for Gwen and hopes she does not sulk all the time, stating that he may as well be dating Courtney.
While walking to the first challenge, Gwen tries to remind her team to work together. However, Duncan does not agree with this notion. Later, Gwen tells Duncan that Courtney keeps glaring at her. Duncan tries to help Gwen's mood by giving Courtney a glare back. When Jo mocks Gwen by telling her to not even think of trying to kiss her, Gwen, in the confessional, is annoyed that despite every nice thing she has done for three seasons, her kiss with Duncan has reduced her to "evil kisser" status. Gwen then states that she is still adamant that Duncan and Courtney were over before they started dating, claiming Duncan was single at the time. During the challenge, Sierra comes over and tells them many blog readers were upset about Duncan and Gwen's relationship. Despite these readers, Sierra claims that she gets their relationship, saying "love is love", comparing them to her and Cody. Gwen sarcastically agrees. Before Duncan jumps off the cliff, he asks for a kiss for luck. However, Gwen feels uncomfortable about Sierra staring at them and quickly pushes Duncan off the cliff so he can do his part of the challenge. Gwen is later is pushed by Mike and falls into the water with the sharks. Duncan is visibly concerned for Gwen.
At the beginning of the episode, both Gwen and Duncan are seen having breakfast with Scott, and later Jo. Gwen sits at the farthest end of the table alone, and is visibly upset when Duncan and Scott toast their villain status. Duncan asks if she is all right, calling her "dollface" in the process. She responds by saying she is simply concerned about Lightning, who is at Boney Island searching for the McLean-Brand Chris Head. When the challenge is about to begin, Gwen is still depressed over being on a villain team and doesn't notice Duncan flirting with her, which visibly annoys him. Later, Gwen finds one of the 3D puzzle pieces to their team's landmark. Duncan goes over to congratulate her, only to set off one of Chris's hidden traps, covering himself in sand. Gwen finds this amusing.
Early in the episode, Gwen notices Courtney is glaring at her while the contestants are walking towards the challenge. Gwen asks Duncan to do something about it but he refuses. During the challenge, Duncan tells Gwen that he believes Gwen is intentionally hurting Courtney, just like what Heather stated earlier. Gwen responds by saying that he doesn't know her at all. When Duncan spots Cameron trying to fire at Gwen, Duncan uses himself as a shield to protect Gwen. Gwen is concerned for him and shoots Cameron with several leeches before going to help her shot boyfriend. Gwen is astonished that he took a leech for her. He responds by saying that she doesn't know him very well either. Duncan's heroic actions allows Chris to switch Duncan to the other team. Before moving to the Heroic Hamsters, Duncan tells Gwen goodbye by giving her a kiss on the cheek.
In the confessional, Duncan wonders how Gwen is doing. Gwen's confessional is then shown where she is crying for not being able to apologize to Courtney. Before the challenge, Duncan blows a kiss to Gwen, something that he quickly realizes he has never done before. She also notices this and brushes it off. Duncan encourages Gwen to keep moving forward during the obstacle course, despite now being on different teams. He voices his concern when her face turns green, before she pukes on him and knocks them both off the logs.
Halfway through the episode's challenge, Duncan and Gwen come across each other as they're both running away from the crazed forest critters. Duncan saves Gwen by tossing his sausage tail to distract the animals away. As they're catching their breath, Duncan suddenly asks Gwen about what Courtney has said about him now that Gwen is on the same team as her. Gwen, visibly annoyed by the question, asks him as she pokes his head how "such a big ego can fit inside a teeny tiny brain" before telling him that Courtney hasn't said anything about him. Gwen then walks away in indignation. In a subsequent confessional scene, Gwen angrily states that Duncan's obvious obsession about Courtney is very uncool. In a subsequent confessional of his own, Duncan wonders what Gwen's problem is and expresses disbelief over Gwen's statement that Courtney isn't talking about him.
At the elimination ceremony, Duncan comes over to Gwen and kisses her cheek, telling her to cheer up. However, he suddenly asks if Courtney was watching, making it clear that he was simply trying to get her jealous. Gwen, finally fed up with his behavior, tells him that their relationship is over before pushing him away. Gwen then states in a confessional scene that she couldn't believe that their relationship would end like this, and that even though she felt "fireworks" after their kiss in I See London..., his kisses now felt like she was being "kissed by a shoe", and that the thrill in their romance is "so gone."
Duncan wonders why Gwen dumped him, thinking it could be because of his new heroic acts. Later, Gwen tells Courtney that she dumped Duncan, valuing friendships over relationships.
Duncan, feeling that Mal is a threat, attempts to form an alliance with Gwen and Courtney. Neither girl takes his warning about Mike seriously and laugh it off, as Gwen calls Duncan's warning "a million on the lame scale." Later on, Duncan destroys Chris's private mansion (which the host refers to as a "cottage") with a stick of dynamite in an attempt to restore his lost "bad boy" confidence. Duncan succeeds in getting his confidence back but also ends up getting arrested and automatically eliminated from the show. Gwen sarcastically congratulates him and tells him she hopes it was worth it, to which he enthusiastically replies that it was, although he becomes much less excited when he learns he'll be going to prison instead of juvenile hall. Gwen shows no remorse for Duncan's imprisonment.
When Gwen finds out how much Chris' old mansion was wrecked, she sarcastically thanks Duncan for destroying it in the confessional.
It can be assumed the two were friends in an unfinished prototype of Total Drama Island, as Gwen keeps her arm on Duncan's shoulders on promotional picture.
- Both are part of friendships formed in Total Drama Island that involve three people, and the friendships can be considered gender equivalents of each other (Gwen is close to Leshawna and Bridgette while Duncan is close with DJ and Geoff). In spite of this, both have said numerous times that they either have no friends or prefer to be alone.
- This is the second couple to sing a duet, the first being Bridgette and Geoff (Save This Show) and the third being Alejandro and Heather (This Is How We Will End It).
- Both hold interests in the subliminal and supernatural, as they love horror and alien movies. Specifically, they both consider Blood Bath II: Summer Camp Reign of Terror and Alien Chunks their all-time favorites out of those genres.
- This is also seen in their Total Drama Online profiles.
- Both considered tough by the other contestants, and both have proven this on several occasions. Incidentally, both have also proven to have softer sides that they prefer to keep well-hidden.
- Both were suspected of cheating on their former significant others by several characters well before their relationship was made official.
- In Total Drama Action, Duncan is the highest ranking member of the Screaming Gaffers while Gwen is the lowest ranking member.
- This is the first couple in which both members are in the final two at one point in the series; the second being Alejandro and Heather and the third being Mike and Zoey.
- This is the only couple in which both members made it to the final four more than once.
- This is the first couple to be formed in a later season despite both members make their debut on an earlier one and already having several major interactions.
- This is the third couple to consist of a female member of the Screaming Gopher and a male member of the Killer Bass, the others being Lindsay and Tyler and Harold and Leshawna.
- This couple, along Courtney and Duncan, is one of the only couples on the show in which both members compete in four seasons.
- Despite their relationship, both indirectly caused each other's eliminations in Total Drama World Tour.
- Duncan is technically responsible for Gwen's elimination in Picnic at Hanging Dork. If Duncan had never thrown the dingo at Cody, then Cody would have been able to vote for Courtney like originally planned and there would have been no tie-breaker challenge leading to Gwen's elimination.
- Gwen and Courtney's fights were one of the reasons why Duncan had quit the game.
- Also, in African Lying Safari, Heather telling Duncan that he caused Gwen's elimination caused Duncan to get distracted, which led to him being voted out.
- In an interview, it was confirmed that Duncan's voice actor, Drew Nelson, actually prefers this relationship over Duncan's relationship with Courtney.
- Christian Potenza, Chris' voice actor, also seems to prefer this relationship, as stated in an interview
- Both wore a choker and dye their hair partially (and both use a shade of green dye).
- In Total Drama Online interactive feature Get the Look, it is revealed that Gwen and Duncan went to the same salon, unknown to the both of them.
- This relationship was in a love triangle with Courtney and Duncan.
- This is the second couple from the original cast to have both members make an additional cameo in Total Drama: Revenge of the Island; The first being Izzy and Owen.
- Interestingly, Duncan is involved with the elimination of the two masterminds who are behind both of Gwen's eliminations in Total Drama Action and Total Drama World Tour.
- Ironically, their eliminations in Total Drama All-Stars are related to their conflicts with Chris as well as his cottage:
- In You Regatta Be Kidding Me, Duncan destroys Chris' cottage, which leads to his arrest after Chris reports his act of vandalism to the police.
- In The Bold and the Booty-ful, Chris eliminates Gwen on the spot for "defacing" the painting from his cottage, in reality a failed attempt to actually fix it.
- Both, along with Heather and Zoey, are the only contestants to appear in every episode of two seasons:
|Interactions with||Everyone | Alejandro | Beth | Chef Hatchet | Chris | Courtney | DJ | Geoff | Gwen | Harold | Heather | Leshawna | Mike | Owen | Trent | Zoey|
|Other content||Guys' alliances | Scruffy|
|Interactions with||Everyone | Bridgette | Cameron | Chris | Cody | Courtney | DJ | Duncan | Geoff | Heather | Leshawna | Lindsay | Owen | Sierra | Trent | Zoey|