In the television adaptation of Vampire Breath, Cara's name is Cara Renfield, and she is Freddy's twin sister.
Cara is hanging out with Freddy in his family's basement when they discover a secret door. The door leads to a tunnel, and the tunnel leads to a small room with a coffin in it. Inside the coffin is a bottle marked Vampire Breath. When the kids open the bottle, a vampire appears. The vampire uses the Vampire Breath to take himself back in time, but he accidentally takes the kids with him.
The only way that Count Nightwing knows how to get the kids back to their time period is to bite their necks and turning them into vampires. Count Nightwing needs more Vampire Breath before he can turn them into vampires, so he leaves the kids in search of a bottle. The kids try to get to a bottle before him.
Eventually, they find a bottle. Freddy manages to open it before Count Nightwing can grab it from him. The group of three are transported forward in time into Freddy's basement. Freddy's parents come home and explain that Count Nightwing is Freddy's grandfather. Cara thinks that this is weird, but she isn't afraid. While searching the basement's bathroom, Freddy finds a bottle of Werewolf Sweat. While fighting for the bottle, the kids accidentally pull out the stopper and pour some of the bottle's contents onto themselves. Freddy notices that Cara is beginning to growl.
Since Cara is related to Freddy in the episode, the ending is slightly different. Cara is also revealed to be a vampire. Since it's the siblings' birthday, their parents surprise them with bunk-bead-coffins.
Cara and Freddy constantly compete with each other. Each one tries to prove their strength and bravery to the other. While Cara tries to act tough, she becomes genuinely scared when her and Freddy are transported back in time.
Cara is twelve years old and an inch taller than Freddy. She has dark eyes and a round face. Her hair is wavy and black.