Zach Cooper and his mother Gale move from New York to the town of Madison, Delaware. Their new neighbors are the mysterious “Mr. Shivers” and his daughter Hannah, but when Zach tries to introduce himself, Mr. Shivers warns him to stay away from them. At Madison High School where Gale works as the vice-principal, Zach befriends Champ, an often bullied socially awkward student.
One night, Zach hears Mr. Shivers and Hannah arguing from his window, followed by Hannah screaming. He calls the police, but Mr. Shivers assures Officer Stevens and Officer Brooks that nothing is wrong and the scream was from a movie. Fearing Hannah is in danger, Zach tricks Mr. Shivers into going to the police station for further questioning.
Once he is gone, Zach and Champ break into the house in search of Hannah. They find several Goosebumps manuscripts, all of which are locked. They’re confronted by Hannah, who assumes they are burgling the house. Zach clears up the misunderstanding, but accidentally unlocks The Abominable Snowman of Pasadena. The book opens, releasing a Yeti that breaks out of the house. They pursue the Yeti to a local ice rink, but Mr. Shivers appears and sucks it back into the book. On the way home, Mr. Shivers explains he’s truly R.L. Stine, the author of Goosebumps. He created his stories as a child to cope with severe bullying. However, the monsters came to life and became uncontrollable, so he had to trap them inside their manuscripts.