Four mental patients on a field trip in New York City must save their caring chaperone, who ends up being taken to a hospital in a coma after accidentally witnessing a murder, before the killers can find him and finish the job.
A criminal psychologist loses his arm in a car crash, and becomes one of three patients to have their missing limbs replaced by those belonging to an executed serial killer. One of them dies violently, and disturbing occurrences start happening to the surviving two.
