Three years after the nearly catastrophic events that took place in Goosebumps (2015), once more, R.L. Stine's monstrous creations--including the vengeful doll, Slappy the Dummy--come to life, when best friends, Sam and Sonny, bring to light a mysterious book. With Halloween just around the corner, the unsuspecting citizens of Wardenclyffe, New York, must brace themselves for yet another endless nightmare, as the boys inadvertently unleash the unfathomable terrors of an unpublished leather-bound manuscript of Goosebumps. This Halloween, Slappy intends to finish what he has started. Can Sam, Sonny, and his older sister, Sarah, thwart the supernatural megalomaniac's plans?