The conflict between Gwen and Sierra is mostly one-sided on Sierra's side, due to her intense jealousy of Cody's one-sided crush on Gwen. Gwen, on the other hand, doesn't care too much about Sierra, mostly because of her stalker tendencies, as well as her disgusting habits, but they usually seem to get along enough for challenges. When Sierra and the rest of Team Amazon find out that Gwen kissed Duncan, Sierra's hatred for Gwen escalates and she aligns with Courtney to get rid of Gwen once and for all in an effort to make Cody start paying attention to her, and also because she believes boyfriend stealing is wrong. After Gwen's elimination in Picnic at Hanging Dork, Sierra becomes delighted, but then realizes that Cody misses Gwen, much to her own dismay.
Their conflict has subsided by Total Drama All-Stars, partially due to Cody not qualifying for the season, and no longer being interested in Gwen. While Gwen remains disturbed by Sierra's habits, especially her attraction towards Cameron, the latter actually seems to have warmed up to her. Sierra is an avid supporter of Gwen's relationship with Duncan, having made several "Gwuncan" videos. Despite her annoyance, Gwen still shows sympathy for Sierra when she is eliminated in Suckers Punched.
Gwen is grossed out after watching Sierra sniff Cody's shoe, and seeing its lace go up her nose and out through her mouth. After winning the challenge, Gwen calls Cody's helpfulness amazing, to which Sierra agrees, before calling for a group hug. But while hugging Cody tightly, she angrily tells Courtney, Gwen, and Heather to "back off" as soon as they reach closer for the group hug.
Gwen cheers for Sierra when she does well in the apple collecting challenge.
Gwen is disturbed when she finds out that Sierra is using a pizza box as a laptop, and an actual mouse as a computer mouse. She quickly rejects Sierra's offer to use it after she is finished with it. When Chris asks one of the members on Team Amazon to carry Cody's EpiPen, Cody begs Gwen to take it instead of Sierra, who reluctantly agrees to do so, much to Sierra's dismay. Sierra complains about this arrangement, claiming that she knows more about Cody's life-threatening allergies than anyone else on the team. When they are caught by the Zing-Zings, Heather orders Gwen to reach into Cody's pockets for the flashlight's batteries. Sierra then complains about not being the one reaching into Cody's pockets. Later, Sierra is annoyed by Gwen's snoring, claiming that she is driving her crazy. After their team loses the challenge, Gwen awakens and asks if they won, to which Sierra and Courtney glare at her. Despite being jealous of Gwen's hold over Cody, as well as angry at her for cursing the team with her good luck prediction, Sierra agrees to vote Heather off with Courtney and Gwen.
After hearing Sierra cry and distract the team throughout the first challenge, Gwen furiously yells that she cannot take it anymore, and leaves her behind with Cody, as she, Courtney, and Heather exit, telling him that he needs to deal with her.
During Changing Guard Mix, Sierra, along with Courtney and Heather, force Gwen to strip the guard. However, Gwen puts a Cody mask over the guard's face, telling Sierra it's Cody, leading Sierra to do it instead.
Prior to discovering the kiss, Sierra approves of the concept of a "Gwuncan" relationship. Later, when Courtney finds out about Duncan's betrayal, Sierra restrains her from attacking Gwen, expressing a worried look on her face, despite siding with Courtney by ordering Cody to lose the challenge, so that the team can eliminate Gwen from the competition. She is displeased when their team ends up winning the challenge, due to Cody wanting to save Gwen.
In this episode, Sierra is shown to have developed a strong hatred towards Gwen. She angrily makes a paper cut-out of Gwen before proceeding to bite the head off, while singing an altered version of the nursery rhyme Rock-a-bye Baby. 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 is wrong. When a lizard climbs up Heather's leg and forces everyone to run into the middle of the minefield, Sierra immediately blames Gwen for leading them to the trap, labeling her as the "New Heather". During Boyfriend Kisser, Sierra makes a comment about how obvious the attraction between Gwen and Duncan is. At the base, none of the teammates are 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.
In the first-class section, Sierra and Courtney glare ominously at Gwen. Sierra joins Courtney's alliance to vote Gwen off if they lose. Additionally, Gwen tries to initiate an alliance with Cody, promising Cody she would help him get Sierra voted off after Courtney if he joined forces with her.
Sierra is delighted that Gwen is finally gone, referring to Gwen as her enemy in a confessional. She claims that Gwen's absence will lead Cody to realize who his true love is, while pointing at herself. Sierra is also mad and proven wrong when Cody constructs a huge wooden replica of Gwen's face.
When it is first thought that Gwen will be returning, Sierra, along with Courtney and Heather, looks disappointed.
When Cody's sleep-talking indicated that he was having a dream about him and Gwen, Sierra quickly wakes him up. When he asks what happened, she tells him that he was having a nightmare.
Sierra tells Gwen that while many fans seem to be upset about her being in a relationship with Duncan, she understands and also states that their relationship is similar to her and Cody's. Gwen sarcastically replies their relationship is just like Sierra's. When Duncan asks Gwen for a kiss before jumping off the cliff, Sierra's enthusiastic stare at them makes Gwen push him off from discomfort.
Sierra sneaks up on Duncan and Gwen whilst the couple is talking about Courtney, and tries to ambush them, but accidentally flings her leech at herself. As it latches into her face, she comments dreamily that it feels just Cody's kiss, making Gwen wretch in the confessional.
Sierra sighs in happiness when Courtney and Gwen rekindle their friendship. When the Villainous Vultures are given the chance to vote off one of the Heroic Hamsters, Gwen speaks for her team and says that they've elected to eliminate Sierra but feels sorry for her. Before Sierra takes the Flush of Shame, Gwen asks Sierra to say "hi" to Cody for her.
- This conflict is directly connected with Cody's attraction to Gwen and Sierra's attraction to Cody.
- In both seasons that they compete in together, one of them places fourth while the other places ninth.
- Coincidentally, in the season where they place fourth, both are eliminated on the spot by Chris due to angering him by destroying something belonging to him.
- Also, in the seasons they placed ninth, they were the last contestants to be eliminated before the merge.
- Both have been eliminated in the seventh episode of a season.
|Interactions with||Everyone | Bridgette | Cameron | Chris | Cody | Courtney | DJ | Duncan | Geoff | Heather | Leshawna | Lindsay | Owen | Sierra | Trent | Zoey|
|Interactions with||Alejandro | Cameron | Chris | Cody | Gwen | Heather|
|Other content||Cody Jr. | Cody 1 and 2 | Sierra's smartphone|