"Killer Rats" is a mysterious horror film that takes place at "The Brookdale Institute", a little-known hospital for the criminally insane. This fact is kept on a need-to-know basis, but the institute also serves as a safe harbor for the chronically drug-addicted rich and famous, as well as the once-famous who have hit rock bottom.
"Jennifer/Samantha" (Sara Downing), a career-driven reporter for "The Philadelphia Enquirer", goes undercover as a patient to investigate possible health code violations at Brookdale. Little does she know, the real story is much more terrifying than she could have imagined.
The hospital is infested with super-intelligent, supernaturally empowered killer rats, a result of forgotten experiments conducted by "Dr. William Winslow" (Ron Perlman), the Chief Psychiatrist at Brookdale. While Winslow abandoned the experiments, ex-patient/caretaker "Ernst" (Michael Zelniker) has developed a symbiotic, telepathic relationship with the rodents.
As patients start to disappear and the body count rises, even the exterminators are no match for the hybrid rodent strain that terrorizes Brookdale.