B-movie horror. Undercover reporter Samantha (Sara Downing) checks into Brookdale Institute, a psychiatric hospital, in the hope of getting a scoop on the recent disappearance of several of the institution's inmates. Unbeknownst to her, the rats from a forgotten experiment have mutated into flesh-eating monsters and infested the hospital, and are now feasting on its residents. As the body count mounts, even Hans the Exterminator (John Paul Young) is unable to contain the deadly force of this hybrid rodent strain. Ron Perlman co-stars as the hospital's director, Dr William Winslow.