With their after school junk business, best friends Sonny and Sam hope to find treasure in other people's trash. But when cleaning out the old Stine house, they open a locked book that frees a supernatural nightmare. Slappy! Now, with the help of Sonny's sister, Sarah, they're in a race against time to get the sinister dummy and all the creatures he's brought to life back into the pages before he unleashes total pandemonium!