Heather Chandler is introduced by Veronica Sawyer in the opening number "Beautiful" as "The Almighty," and then quickly after, "Mythic Bitch."
Veronica would invite the heathers over to her house and soon they would meet her parents before leaving to go to Kurt and Ram's party at their house. During this, Heather drops Veronica off at a 7-11, telling her to get BQ corn nuts before Veronica meets JD. After this, the heathers and Veronica go to Ram's homecoming party, and sing "Big Fun" where the heathers try to make a fool out of Martha "Dumptruck" and Veronica stops them, where Heather Chandler would tell her "No, You don't get to be a nobody, come tomorrow, you're an ex-somebody. You can move to washington, you can move to Jefferson but no one at westenburg will let you play in their reindeer games" to which Veronica would go to throw up on her shoes.
After "Dead Girl Walking" Veronica says she needs to visit Heather Chandler, implying that Veronica fighting and wanting to leave the heathers has happened before. Veronica would then visit her place, where Heather would ask for a prairie oyster to cure her hangover. Veronica would suggest putting a phlegm globber in her drink, while JD says that he'd prefer replacing her drink with cleaning product, which Veronica would eventually give the cleaning product in a mug to Heather Chandler, successfully killing her.