9-year-old Alex Pruitt is home alone with the chicken pox. Turns out, due to a mix-up among nefarious spies, Alex was given a toy car concealing a top-secret microchip. Now Alex must fend off the spies as they try break into his house to get it back.

A rash of bizarre murders in New York City seems to point to a group of grotesquely deformed vagrants living in the sewers. A courageous policeman, a photo journalist and his girlfriend, and a nutty bum, who seems to know a lot about the creatures, band together to try and determine what the creatures are and how to stop them.