It's been four months since Nicky Roth has seen his best friend and neighbor, Aaron Peterson. Aaron's father, a reclusive theme park designer, told the town that Aaron and his sister Mya are living with a relative far away, but Nicky can't seem to accept it. Plagued by terrifying nightmares of robotic mannequins, rotting theme parks, and a dark basement, Nicky teams up with his friends from school to find out what really happened to Aaron and Mya. Together, they start piecing together a picture more disturbing than they could have imagined. The screams coming from the neighbor's house can't be nothing, and Nicky is determined to get to the bottom of where his friends went, and what-if anything-can be done to save them.