Famed psychiatrist and known ladies man Dr. Palmer Harrison is found murdered in his office after the end of the working day. He died with an erection, leaving the police investigators to suspect initially that his sexual partner at the time is the murderer. Their lead suspect is who is listed as his last patient of the day, heiress Karen Wettering, whose father, Charles Wettering, is dismayed at whatever negative publicity his children, especially Karen, are always the center of. Karen categorically denies having attended that scheduled session or having killed Palmer, but she does admit to having had a sexual relationship with him. Roger Bellamy, Karen’s lawyer and friend, asks his friend, recently widowed psychiatrist, Dr. Peter Rexler, to conduct an initial psychiatric evaluation of Karen to make sure there are no hidden skeletons with which he has to worry in court. That meeting leads to a sexual relationship between Karen and Peter, who now has a vested interest in seeing that nothing bad happens to her. But as evidence continues to mount against Karen and as Roger in turn scratches his head in how best to defend her, Peter comes up with a solution - manufacture a medical lie, albeit a dangerous one - that will at least give Roger some time to mount a credible defense. What they are all unaware of is that a sexual history diary that Palmer kept - with which Palmer’s assistant is blackmailing Roger and Karen, but which Roger believes is merely an embarrassment than conclusive evidence against Karen - contains crucial information as to the murderer’s motives.