Rats (2003) on Netflix

Plot summary

Brookdale Institute, once a prison, is now a hospital for the criminally insane that also admits patients it does not advertise: wealthy drug addicts and once-famous people whose families have tried everything else. Its condition is crumbling and its money is short. Samantha, a reporter for The Philadelphia Enquirer, checks in as a patient named Jennifer to look into possible health code violations and leave with a story. Dr. William Winslow is the chief psychiatrist. Beneath the building lie tunnels and old sewage viaducts, and the rats down there feed on blood. Patients have gone missing. Exterminators Hans and Jim are brought in to deal with the infestation.