An airplane carrying several counterfeit paintings, worth millions to the counterfeiters, suffers a malfunction in the cargo hold, spilling the paintings, as well as all the luggage, near a colony of cave men that has existed unaltered in the middle of America for millenia. Two of the men from the colony find the crashed luggage and begin to assimilate themslves into modern culture using the luggage, and that's when the fun begins. When the counterfeiters come in search of their loot, they find a lot more than they bargained for!

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 photojournalist 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.