Dawn and Vin didn't interact often before Total Drama: Revenge of the Island. They didn't interact much at all in the first few episodes on Revenge of the Island due to being on opposing teams. Vin states in Blow 'Em Sky High that he always loved Dawn. Dawn is eliminated in Chef's Mutant Dinner Hunt, but soon returns in Jeepers, It's a Creeper. Vin greets her lovingly. Dawn is placed onto the same team as Vin. They both have a crush on each other, but they don't know about the other's feelings towards them. Dawn becomes more open to showing her feelings towards Vin and they eventually both reveal their feelings for each other, becoming a couple in Blow 'Em Sky High. Their relationship is strained and temporally ended after Vin wins the challenge in The Treasure of the Sierra... or is it Chris's?, and is able to choose who to eliminate. Vin chooses Scott, unknowing that he has an immunity idol. Scott then chooses to eliminate Dawn. Dawn blames Vin for her elimination, and breaks up with him. Dawn's elimination and their break up causes Vin to go into a temporary insanity in Let's Kill Cody, which leads to him being disqualified from the competition. However, in The Virulent Finale: Malevolent vs. Devious, they are placed on Mal's team as his helpers, and they reconcile after Vin saves from her possible death. Vin and Dawn stay as a couple going into Season 5.
In the beginning Dawn and Vin didn't interact with each other as much. Dawn was eliminated in the fifth episode. However, it is hinted that Vin always had a crush on Dawn and soon falls in love with her at some point before Dawn does too. This is not revealed until the episode Dawn is eliminated again though, as when Dawn asks Vin if he loves her, and Vin replies "I always loved you".
Their relationship soon starts in the episode, Jeepers, It's a Creeper when Dawn returns and Vin immediately greets her lovingly, happy that she is back. Dawn then holds his hand, making both of them blush without either of them knowing their attraction for each other. Therefore, Dawn enjoys being with Vin, as they are now in the same team, while Vin is also happy that Dawn is with him, so during the challenge they now try to compete together and help each other. In the next few episodes, since they both think their relationship is one-sided, Vin and Dawn continue to compete with each other, but never reveal their feelings, so they only stay as friends, even though they continue to like each other. Also, when Vin gets sad, Dawn is also there with him, so soon they start to show their affection for each other, but a full relationship never starts as long as they keep their true feelings secret. When, Vin gets hurt though, Dawn gets mad at Chris, and then everyone asked why does she care, when no one else cares about Vin. This makes Vin like Dawn more, as she is the only girl who treats him like a real human being.
Finally, it is not until the episode Blow 'Em Sky High when the relationship starts. Dawn first starts to see hints that Vin does indeed like her back, and by knowing that, she soon tries to make Vin reveal his true feelings for her. Having Vin win the last challenge, Dawn then goes ahead and congratulates Vin, making him very happy. Dawn then asks Vin that if he can win again, but this time for her. Vin, now possibly already in love with Dawn, agrees and wonders why Dawn asked him that, but ignores logic and just goes with it. Meanwhile, Dawn continues to care for Vin by treating him nicely and when Dawn gets hurt by Lightning, Vin also gets worried for her. Once the challenge starts, Dawn is the first to go. However, due to her conflict with Lightning, Vin then gets beat up by him and Dawn gets distracted. Vin then beats up Lightning instead, making Dawn complete the challenge. Dawn and Vin then go against Lightning, and Dawn tells Vin that if he wins, then Lightning needs to go. Vin then goes up next and performs in the challenge with Dawn cheering. As soon as Vin wins, Dawn then gets really happy and tells Vin that she loves him. Vin then gets shocked, and since Lightning calls him Dawn's boyfriend, Dawn gets shocked too. Dawn then thanks Vin for keeping his promise, and now they they are happy for each other, they finally share their first kiss. Dawn immediately gets super happy and finally confirms that Vin does like her back.
However, this doesn't yet start off the relationship, as Vin thinks that Dawn saying that she loves him was just his imagination and that he only heard that because he was so happy, and also that he only kissed Dawn because Lightning and Chef made them do it. Therefore, Vin continues to deny that Dawn likes him back, while Dawn wonders why Vin doesn't get with her yet, so she tries to do what she can to make Vin say that he loves her back. It is not until Vin wins once again in the next challenge that Dawn gets happy and kisses Vin accidentally, finally making Vin realize that Dawn does have feelings for him, so Vin kisses back, this time for real. Dawn then asks that they need to reveal their secrets so she tells Vin that she likes him so much, finally making Vin say that yes, he loves Dawn and always had, therefore officially starting off the relationship. Dawn then gets shocked that Vin loved her all this time, and soon regrets not revealing her feelings for him earlier and wonders all the time they could of been together if she would of been brave and not embarrassed. Vin then reveals that the only reason why he also didn't express his true feelings for Dawn was because he thought everyone would make fun of him, that he likes a lame weak girl.
This relationship doesn't last for long though, as even though Vin won again, this time he didn't get to choose Dawn safe, and instead get to choose to gets to go home. Dawn instantly told Vin to vote for Scott, since she hated him, so Vin goes ahead and does that. That single vote however, backlashed as soon ruins everything, as Scott was deemed safe thanks to an immunity idol, meaning that it was now Scott who got to choose who to be eliminated, and unfortunately for Vin, Dawn who was chosen, making Vin and Dawn really mad, and Dawn runs and swims away in horror. In the episode, Let's Kill Cody, Vin goes into a major depression, saying that the only person that cared for him is gone, and soon goes crazy, beating up Cody while singing "Singin' in the Rain" and then beats up Chris as revenge for letting Dawn go. Chris then disqualifies Vin, and Vin is hurled on the Hurl of Shame by Chef. It is not until the third aftermath, where Vin and Dawn see each other again, but Dawn starts complaining, blaming Vin for her elimination in the interviews, when it was actually Scott's fault. Vin tries to tell her that it was not his fault and it was Scott's. Dawn doesn't forgive Vin though, and continues to blame him and stating that he betrayed her. During the Final 2 Reward Challenge, Vin and Dawn are paired up again on Team Mal. Dawn is not happy about this but Vin goes with it anyway. Vin scores some points, but Dawn does not care, and they end up losing.
In The Virulent Finale: Malevolent vs. Devious, Dawn and Vin are chosen to compete together again, as helpers for Mal. Dawn is first not happy about this, but soon she realizes that it was never really Vin's fault, and was in fact Scott's fault she was eliminated. Dawn apologizes to Vin for not trusting him and asks him to work together so they can take down Scott once in for all. Vin, though still mad at Dawn for blaming him for her elimination, agrees and both of them then compete together by helping Mal throughout the challenge. A mutant eagle attacks Dawn and causes her to fall into a canyon filled with lava. She is able to hang on to the edge, and calls Vin for help. Vin, still loving Dawn, throws the egg to Mal and runs over and saves her. They soon kiss. Dawn apologizes for what happened and they get back together as a couple. Vin and Dawn then happily fly over the canyon on the giant mutant eagle along with Mal. Ezekiel and Cody however throw rocks at the eagle, knocking it out. Ezekiel tackles Dawn and Cody tackles Vin, leaving Mal to win the challenge himself. Dawn eventually breaks out, and tampers with Scott's jetpack, and launches it towards Scott and Mal, causing their eggs to blow up. Scott and Mal are blown past the finish line, with Mal winning by grabbing onto Scott's egg 0.001 seconds before crossing. Dawn and Vin cheer in excitement as Scott was finally eliminated. Vin tells Dawn, "don't ever leave me again", which Dawn promises to never do so. The couple soon kiss many times while they cheer along with the others. Cody tries to hook up with Dawn, but Vin pushes him down. After Chris is arrested, Kevin the Intern injures Vin to appease Chris, but Dawn beats him up to protect him.