Heidi Davidson is riding a bus heading to Shepard Falls in Vermont. After her parents died in a car accident, Heidi has been sent to live with her uncle, a scientist named Dr. Palmer Jekyll. She hadn't seen or spoken to Uncle Jekyll or his daughter Marianna in seven years since she was five years old. Heidi is left at a bus station with nobody waiting for her. She is soon greeted by a boy her age named Aaron Freidus. When she tells him about her uncle, he panics. He tells Heidi that the town has had to deal with attacks by a horrible beast every night and that Dr. Jekyll is the one to blame. Heidi laughs at Aaron, believing he was just trying to scare her with the story of Dr. Jekyll and Mr. Hyde.