Gwen and Sierra

The Gwen-Sierra Conflict is about the conflict between Sierra and Gwen in Total Drama World Tour. By the Total Drama World Tour episode, The Am-AH-Zon Race, it is shown as a very minor issue, but seems to grow into a larger conflict in Greece's Pieces, and continues throughout the rest of the season, even after Gwen's elimination.

Overview
The conflict between Gwen and Sierra is mostly one-sided on Sierra's side, through Cody. She rarely mentions it, though, pretending her disgust is because of other reasons. It reached a high point after the events of Greece's Pieces, when Tyler revealed that Gwen and Duncan kissed, a revelation that intensified during The Ex-Files. further during The Ex-Files.

Super Happy Crazy Fun Time Japan
Gwen, along with Heather and Courtney, are grossed out after watching Sierra sniffing Cody's shoe. After winning the challenge, Sierra calls for a group hug, but she denies it to Gwen, Courtney, and Heather (most likely due to not wanting anybody but herself hugging Cody) and telling them to "back off".

The Am-AH-Zon Race
Gwen is freaked out by Sierra when she uses a pizza box and an actual mouse as a laptop and quickly rejects Sierra's offer to share it with her. When Chris asks for a team member to carry Cody's epipen, Cody begs Gwen to take it instead of Sierra, which she has to agree, much to Sierra's discomfort, claiming she knows more about Cody's life threatening allergies than anyone. When they are caught by the Zing-Zings, Heather orders Gwen to reach Cody's pockets for the lantern's batteries, then Sierra complains about not being the one reaching Cody's pockets. Later, Sierra is annoyed by Gwen's snores, claiming they were driving her crazy. After the team lost the challenge, Sierra and Courtney glare at Gwen when she wakes up and asks for the results. Like Heather, Sierra thinks Gwen is responsible for jinxing the team. She then agrees to vote Heather off for their loss, if Gwen promises to stop being nice to Cody because of Sierra's attraction.

Can't Help Falling in Louvre
After hearing Sierra cry throughout the first challenge, Gwen furiously yelled that she couldn't take it anymore, and left Sierra behind with Cody.

Greece's Pieces
After learning about Duncan and Gwen's kiss, Sierra sides with Courtney by ordering Cody to lose the challenge so that the team could eliminate Gwen, although she does hold Courtney back from trying to attack Gwen when she learns the truth.

The Ex-Files
In this episode, Sierra is still shown to have developed a hatred towards Gwen, along with Courtney. She makes a paper cut-out of Gwen and then bites its head off. While doing this, she chants a strange rhyme gong "the cradle will fall, and down will come Gwen!". Later, in the confessionals although she says that she saw Duncan and Gwen's attraction coming since season one, she still believes that stealing other girls' boyfriends was wrong. She even seems as furious at Gwen as Courtney. When a lizard climbs up Heather's leg and everyone ends up in the middle of the minefield, Sierra immediately blames Gwen for leading them to the trap, labeling her as the "New Heather" (even though it wasn't her fault). Though she doesn't sing in Boyfriend Kisser, she does make a line about how obvious Gwen and Duncan's attraction was. At the base, none of the team is able to find an artifact, until Gwen finds the alien cube. Sierra and Courtney are the only ones upset at her, seeing as how she won the challenge and made herself safe.

Picnic at Hanging Dork
At the first class section, Sierra and Courtney keep staring at Gwen, even not bothering Cody for a while. Sierra joins Courtney's alliance to vote Gwen off. Additionally, Gwen tried to be in an alliance with Cody, saying to Cody she would help get Sierra voted off. In the end of the episode Gwen and Courtney end up in a tie. Courtney wins the tiebreaker, eliminating Gwen.

Sweden Sour
Sierra states this day is the best, as Gwen is finally gone. She appears in the confessional saying that she's happy about Gwen's elimination, and that Cody can finally remember who is his true love, while pointing to herself. She adds that Cody probably already forgot about Gwen, even though it was quite the exact opposite. Sierra is also mad that he'd constructed a huge wooden replica of Gwen's face in Gwen's Face.

Awwwwww, Drumheller
Sierra called Cody's dream involving fantasies of him and Gwen a nightmare.

Anything Yukon Do, I Can Do Better
Gwen is seen smiling when Sierra hugs Cody to get warm. Although, it might have been because in the previous scene, Cody was attempting to make a move on Gwen by hugging her; therefore, Gwen could have been happy that Cody was leaving her alone.

The Am-AH-Zon Race
Despite being jealous of Gwen, and being mad at her for cursing the team with her good luck prediction, Sierra agrees to vote Heather off instead of her, on the condition that she wouldn't interfere with her and Cody.

Greece's Pieces
Prior to discovering the kiss, Sierra does acknowledge and appears to approve of the "Gwuncan" relationship, even stating that it has existed in the series since season one. Also once Courtney found out about the kiss, Sierra physically restrained her from attacking Gwen and had a genuine look of concern on her face.

Trivia

 * Both of them have an unnatural hair color; Gwen's hair is black with teal highlights, while Sierra's is violet.
 * They are two of the three characters to have unnaturally colored hair, the other being Duncan.
 * They both have written blogs.
 * Both are the only female competitors in Total Drama World Tour to have been shown to be immune to Alejandro's charm.
 * Both made it to the final four and were in every episode of their first season; Gwen in Total Drama Island, and Sierra in Total Drama World Tour.