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!

If one could turn back time, could they win back the love of their life? That is the problem puzzling Stillman, a physics genius recently dumped by his stunning girlfriend Debbie. Therefore, after creating a timeline of their romance and a machine to rewind the past, he grabs his wingman Evan and sets off to right every wrong he made with Debbie. However, as this insane comedy proves, there are some mistakes too perfect for science to fix.