In the small town of Wardenclyffe on Halloween Night, two boys named Sonny (Jeremy Ray Taylor) and Sam (Caleel Harris) find a manuscript in an abandoned house that was previously owned by R. L. Stine called "Haunted Halloween." When they open it, they unknowingly release Slappy, (Avery Lee Jones) who plans to cause a Halloween Apocalypse with the help of his monster allies. Now Sonny and Sam, alongside Sonny's sister, Sarah (Madison Iseman), must work to thwart Slappy's plot before all is lost. Directed by Ari Sandel; Starring Madison Iseman, Wendi McLendon-Covey, Ken Jeong, Chris Parnell, Jeremy Ray Taylor, Caleel Harris.