****SPOILERS**** After the mysterious deaths and one suicide of a number of patients at the prestigious Robb Psychatric Clinic it's decided to have SFPD inspector Steve Kerller, Michael Douglas, go undercover there as a psychiatric patient to finds out just what's going on there. Faking mantel illness Keller make It point to get very friendly with the person who was on the scene of one of the strange deaths there Susan Howard, Belinda Montgomery.
Slowly getting Susan to confide in him Keller finds himself being set up as the next victim there by whoever is doing the murdering.It's when Keller gets in touch with his boss on the SFPD who's acting as his uncle Let. Mike Stone, Karl Malden, that the killer goes into overdrive in order to not only have him murdered by slipping a drug in his drink that would induce suicide but Susan as well. That's for her staring to recover her memory in knowing who he is and identifying him to the police!
***SPOILERS*** In him putting his both life as well as mantel faculties on the line to solve this baffling case almost had Inspt. Keller fly out of a six floor window thinking he was a bird flying south for the winter. It was in fact Susan who kept Keller from taking his final dive or flight by getting him to get off the ledge of the building, by pretending to fly along with him, and have him rescued by non other then the director of the clinic Dr. Jonas Robb, James Olsen,who up until then was the #1 suspect in the string of unsolved deaths that happened there.
As for the eventual killer he meant well, in his disturbed mind, in what he did he murdered or in his mind etherized his victims to keep them and their families from unnecessary suffering. He also kept the clinic from going into bankruptcy in the money he got from the victims families in, so he thought, doing what he did!