When Carolyn was only a baby, she was bitten by a werewolf. Somehow, she manages to keep her lycanthropy a secret from her family for fifteen years. Perhaps because of her condition, Carolyn is rather reclusive. Her perpetually drowsy, minimally-articulate mannerisms either evidence or simulate "stoner" behavior as part of her general teenage rebellion, signature of the seventies counterculture. Feeling restricted by her formidable mother, dismissive of her cousin David, and constantly wary of her secret, Carolyn plans to run away to Manhatten when she turns sixteen if her mother doesn't allow it. When she is introduced to Victoria Winters, David's new governess, she's momentarily enthused to learn that the woman is from New York. Even so, she warns "Vicky" that none of David's prior governesses have lasted more than a week before slamming the door in her face, revealing a metal "Keep Out" sign posted on its exterior.
At dinner that evening, Carloyn plays a record in the dining room and dances hippie-like to the song "Season of the Witch" until her uncle Roger angrily demands she turn it down. Grudgingly switching it off, she slumps into a chair as if hopelessly bored at the far end of the long dining table, away from everyone else. She cruelly mocks her cousin David about being "loony" for believing he can still communicate with the spirit of his late mother until her mother orders her to stop.
Carolyn angrily storms out, complaining that the family "tiptoes" around David but no one seems to care how she feels. When a strange pale man bursts into their home one evening acting as if he owns the place, Carolyn is scornfully unimpressed, even when he assumes that she's a prostitute. After her mother questions the man, it turns out that he is Barnabas Collins, a distant relative from England. Weird as he is, he does breathe new life into the Collins family and motivates them to restore Collinwood manor and the Collins Canning Company to their former glory.
Despite Carolyn's disdain for him, Barnabas nonetheless turns to her for advice on his attempts to woo Victoria. Even though she appears to be barely concealing her disgust, she does encourage him to hang out with regular people so he can learn to be less weird.
When Barnabas later declares that the family should host a ball, Carolyn corrects him that people don't have balls; they have happenings and says that if they're going to throw one, they must have a mirror ball and hire Alice Cooper to perform. She's uncharacteristically delighted when he actually obeys her requests. She even speaks into a microphone the introductory words of a song for Alice Cooper: "The Ballad of Dwight Fry". She seems to direct the song's question about a father's whereabouts specifically at her mother, who is not amused.
A day or so after the happening, the mirror ball falls and nearly crushes David. Luckily, Barnabas manages to pull the boy out of the way, but stands directly in the sunlight in the process. Carolyn can only stare along with the rest of her family as Barnabas bursts into flames, revealing him to be a vampire. Handyman Willie Loomis douses him before he's seriously injured, but the damage is nevertheless done. Presumably, Carolyn is amazed that she's not the only monster in the family.
Some time later, Angelique Bouchard, the owner of a rival fishing company, leads an angry mob to Collinwood to demand Elizabeth's arrest. As she accuses Elizabeth of helping Barnabas with murder and arson, Carolyn senses that her lycanthropy is about to activate and quietly slips away so she can privately transform in her room. She's perched herself among a support beam out of the way when suddenly, Angelique is hurled through her bedroom floor. A startled Carolyn is furious at the intrusion and roars at the woman to get out, which she does by magically floating down to the foyer. Peering through the giant hole in her floor, Carolyn sees that her house is on fire and her family is in danger from Angelique, who is actually a two-hundred-year-old witch that cursed Barnabas to be a vampire in the first place.
Carolyn leaps down from her room to defend her family from Angelique's powers, impatiently shrugging off her mother's shock that her daughter is a werewolf. Although she manages to attack Angelique twice, she proves to be no match for the witch and is soon knocked unconscious. Angelique gloats to Elizabeth that she was the one who sent a werewolf to bite Carolyn years ago in her crib because she felt that the Collins line was getting dull, and knew that a werewolf in the family would cause them more misery.
After Angelique's eventual defeat, Carolyn regains both consciousness and human form. Her tough, rebellious façade momentarily forgotten, Carolyn hugs her mother as they and David watch their home burn to the ground.