The Unearthly

At his psychiatric institute, Dr. Charles Conway secretly researches artificial glands in a bid for longevity. He works with his enforcer Lobo and assistant Sharon Gilchrist, using unsuspecting patients for illicit procedures. The experiments take place in the basement operating area, far from prying eyes.

Dr. Loren Wright delivers Grace Thomas, a patient seeking help for depression. Wright reveals his plan to fake Grace's suicide by tossing her belongings into the bay to mislead relatives and authorities. Conway shows a wary interest but demands a controlled demonstration of progress.

Conway takes Wright to the basement and introduces Harry Jedrow, a patient who is alive but severely disfigured and in a vegetative state. Wright is alarmed by how unstable the procedure seems. Conway insists the progress proves the method works.

That night, Frank Scott is identified as an escaped convict by Conway. Rather than turning him over to the police, Conway offers him participation in the experiments. Scott accepts the risky opportunity, hoping for a better outcome.

The following morning, Scott meets Grace alongside Danny Green and Natalie Andries, two other patients slated for treatment. Tensions rise as the group learns their fate may be determined by the sinister experiments. The facility's atmosphere grows increasingly claustrophobic.

Wright pressures for a certificate, while Natalie is sedated and subjected to the artificial gland with a high electric dosage. The procedure backfires, transforming Natalie into a senile old woman. They hide her away to conceal the botched result from the others.

Lobo buries Jedrow alive as ordered, but Frank Scott sneaks to the burial site and opens the coffin. Jedrow rises and escapes, while Lobo, unaware, buries the casket again. The escaped subject suddenly becomes a looming threat to the house of experiments.

Sharon confronts Conway about his apparent affinity for Grace and requests to be the next subject. The tension between staff and the ethical boundaries of the experiments tighten. The intention to pursue more tests becomes more pronounced.

Scott attempts to reveal Conway's unethical deeds to the other patients. He manages to show Grace and Danny what happened to Natalie, but he is quickly caught before he can warn everyone. The conspirators consolidate their control over the group.

Danny distracts Lobo, allowing Scott to escape and confront Conway. Lobo fatally shoots Danny, but Scott overpowers Lobo with his own gun. The confrontation escalates toward a climactic showdown.

Scott is revealed to be Lt. Mark Houston, an undercover police officer, and confronts Conway with Lobo's gun. Conway escapes arrest temporarily, but Jedrow kills him. Lobo then kills Jedrow, setting the stage for a police raid.

Police backup arrives, arrest Lobo and Sharon, and rescue Grace just in time from a scheduled procedure. They discover Danny's body and a hall of failed subjects, prompting the captain to wonder aloud about the implications of immortality.