With Sierra being one of Heather's new potential allies in the beginning of Total Drama World Tour, Heather decides to go after her from the start. However, having seen the first two seasons multiple times and knowing of Heather's reputation on the show, Sierra is fully aware of what Heather has in mind, and decides to use Heather's manipulations to her own advantage. Ultimately, they end up together on Team Amazon.
Both attempt to manipulate the other for their own motives, which ranges from complete friendship to utter disrespect for one another. Heather admires Sierra's knowledge of the show, but sees her as utterly insane, while Sierra sees Heather as a fellow female friend, but knows of her evil and manipulative ways. Ultimately, however, by the end of the season, the two put their differences aside in order to get rid of Alejandro after realizing what he's up to, which ultimately fails when Chris personally eliminates Sierra for blowing up the plane.
When Sierra says that she knows everything about everyone (including their dental records) Heather scoffs at her and calls her a stalker.
Heather tries to form an alliance with Sierra to counter Alejandro's possible alliance with Lindsay. Heather feigns liking Sierra, but in reality is very annoyed by her. In the confessional, Heather says "I do not heart the new girl". Heather chooses to ally with Sierra and Cody during their journey under the pyramid, working together to escape from the "mummy" chasing after them. While the two go through the pyramid, Sierra sets off a trap that sends a row of arrows toward Heather's head, Heather is visibly angry, but she is able to control herself, and pretends to forgive Sierra. Heather joins Sierra in a group hug with Cody, although she is very reluctant to do so and forces an insincere smile. Sierra seems to be unaware that Heather dislikes her, which appears to be quite odd, since Sierra supposedly knows everything about the contestants, and should know of Heather's manipulative nature. After crossing the finish line, Sierra requests for Heather to join her and Cody in a group hug, making Heather slowly and awkwardly join in.
Heather quickly agrees to switch Izzy for Sierra, as she believes Sierra's weaving skills could be vital for the challenge. She starts to regret this after she realizes that only Izzy could control their camel.
When Courtney argues to be the team leader, Heather reminds her that she's not the only person on the team, and her "friend" Sierra is worth considering. As this is mentioned, Sierra sniffs Cody's shoelace, causing it to go up her nose, making Heather disgusted and nearly vomit, asking if any more barf bags are lying around. After their team wins, Sierra cheers "Group hug!" and hugs Cody, but when Heather, along with Courtney and Gwen, try to join in when they hear Sierra's Sierra words, Sierra warns them to back off, scaring them.
Heather reaffirms her need to manipulate Sierra (and Cody by consequence) in order to survive on a team with Gwen and Courtney, when they publicly acknowledge that they want to eliminate her next. When Sierra wants to hug Heather, she rejects it. In the confessional, Sierra states that she knows that Heather is playing her, so she's playing Heather back by pretending to be played. Later, when Team Amazon is receiving their rewards, Heather tells Sierra to not talk to Chris so that he'll forget how creepy she is; however, Heather quickly corrects herself by calling her "special" instead.
Heather is seen sitting with Sierra in the winner's class cabin. Sierra is telling Heather about how she became the president of her fifteenth Total Drama fan club. Heather isn't very interested, and changes the subject, asking if Sierra has any idea of who will be eliminated next. Sierra confirms and states that Team Chris Is Really Really Really Really Hot is the next to lose, due to overconfidence. Sierra then states that, despite Heather being a Total Drama regular, she's a "mega-noob". Heather, not knowing what this word means, confusedly thanks Sierra. Right after this, Sierra appears in the confessional and says that every time Heather tries to use her, she makes a little notch on her belt. She takes it off from her pants, showing seven notches on her belt, but her pants also slip down in the process. During the sausage stuffing challenge, Heather points out that it is Sierra who is making them lose, due to making a statue of Cody out of their meat instead of her when accused by Courtney of not helping out.
When Heather finds out that the Zing-Zings were just teenage Peruvian actors, Sierra comments that Heather isn't the goddess she thinks she is. Sierra decides to join Gwen and Courtney in voting Heather out, but in return, makes Gwen promise that she wouldn't be as nice to Cody. She along with her teammates, are shocked when Chris revealed it was a fake elimination, and appears frightened when Heather glances at her team intimidatingly.
After Alejandro points out that her team is a mess, pointing to a crying Sierra eating ice cream from her bare hands, Heather irritatingly drags Sierra away by her hair. Heather shows consideration for Sierra during her singing of Paris in the Springtime, yelling at Cody to take care of her, and make sure she gets what she needs to get over her sorrow. However, this may have only been because Sierra's crying was annoying and ultimately bringing the team down.
Heather calls Sierra "Fanzilla" when she ends up splashing her, Courtney, and Gwen with her dive.
Heather asks herself if there is anyone sane left around after seeing Courtney and Gwen bond over poop juice, and responds with "That'd be a no", once she sees Sierra updating her Tweeter, using a pizza box as a computer.
While trying to get Alejandro's attention away from Courtney, Heather claims that she has some gum on her butt. However, Sierra ruins it as she points out to Heather repeatedly that she doesn't have any gum on her, either unaware, or simply annoyed by Heather's ploy. Later on, when Heather attempts to hit Cody for building a wooden replica of Gwen's head, using a metal hammer, Sierra immediately lunges at her with a metal rod, yelling "En garde!" As the two of them duel, Heather accidentally knocks Courtney over in the struggle. It seems that the both of them (as well as Cody) agreed to team up in order to vote off Courtney, and both are visibly annoyed when told it is a non-elimination episode.
While Sierra is trying to rescue Cody, Heather (who is fleeing from a lion) runs into her, and they both fall over. While Heather is still panicked from the lion, Sierra slaps her and points out the dilemma that Cody is stuck in the tree. Sierra devises a plan to get him down, but Heather, seeing a way to win Cody's loyalty, diverts Sierra's attention away to some Ezekiel tracks.
After Alejandro chooses Cody as his flight partner in the previous episode, Sierra uses Heather as a psychiatric adviser to help try and figure out what is wrong with the two of them, as they both are stuck in the loser class. As Sierra vents about how she misses Cody (since Alejandro took him to first-class with him), Heather rants in the confessional about what the rude things she would have said to Sierra if she wasn't her only chance, but wanting Sierra as an ally she refrains from speaking this directly to her. Heather tells Sierra that boyfriends are temporary, but girlfriends are forever, as well as adding that Alejandro is trying to destroy her marriage with Cody and advises for her to get rid of him. Sierra proceeds to make fun of Heather and Alejandro in the confessional, and how they are obsessed with each other. Even though she is paired with her for most of the challenge, Sierra admits that alliances don't work, and that she refuses to ally with anyone that isn't Cody. After "giving birth" to a second Cody in the form of a condor chick, Sierra becomes frustrated when it chooses Heather as his mother over her. By the end of the episode, Heather finally admits that Sierra is insane, and can't be trusted in any true alliance. It is presumed that Heather voted off Sierra that night, but the latter was spared when it was a non-elimination.
While talking with Alejandro about the reason for her inviting him to first class with her, she says that if she separated Sierra and Cody then Sierra would try to get her eliminated. After Alejandro makes a fake digital photo of Cody and Heather sleeping together in the loser class, Sierra becomes angry at her throughout the challenge. While the contestants were searching for stuff to use in the design-o-saur-it challenge, Sierra squirts glitter glue in Heather's face out of her fury, to which Heather responds, "Real mature!" Later, Heather voted for Sierra's dinosaur as the best one created. Sierra also votes for Heather's dinosaur because she loves the idea that it was a Chris dinosaur and said she'll have to remember that idea. After Sierra wins the first part of the challenge, she attempts to use her newly received post digger to attack Heather, frightening Heather and making her flee in fear. Eventually, Sierra finds out about the truth between Cody and Heather, and the photo was a fake. When Heather is in the confessional, Sierra pops in and Heather jumps away, begging her not to murder her. Later, when Sierra accidentally blows up the plane, Heather appears to be concerned for her and runs towards her alongside Alejandro and Cody. Heather asks Chris about Sierra but he doesn't care too much.
When Cody digs up Sierra from the rubble, Heather gets her a wheelchair and a green feathered hat from Rapa Phooey! In the confessional, Heather says that she knows what it's like to be bald and that no girl, crazy or not, should have to be bald on television, feeling somewhat sympathetic towards Sierra. Later, Sierra states to the fireworks salesman that she can't let Heather win.
In Heather's ending, Sierra cheers for Heather when she kicks Alejandro in the groin and wins the season, along with the one million dollars prize. She also looks concerned when Heather and Ezekiel fight over the million dollars.
Heather and Sierra are seen fighting over a treasure chest underwater.
- Both have lost their hair during the elimination episode of the first season they participated in. In addition, after their hair would grow back they would tie it into a short ponytail.
- Both were eliminated back-to-back with Duncan in the first season they competed in, ranking one place above him.
- Both of them appeared in every episode of a season despite not being a finalist.
- Both, along with Alejandro, Cody, and Ezekiel, are the only contestants from Total Drama World Tour to have been through every single location.
- Both placed ninth in the second season they competed in.
- Additionally, both are eliminated one episode before the merge.
|Interactions with||Everyone | Alejandro | Beth | Chris | Cody | Courtney | DJ | Duncan | Gwen | Harold | Leshawna | Lindsay | Owen | Sierra|
|Other content||Heather's alliances | Heather's hairstyles|
|Interactions with||Alejandro | Cameron | Chris | Cody | Gwen | Heather|
|Other content||Cody Jr. | Cody 1 and 2 | Sierra's smartphone|