Finally getting to spend a bit of leave time with his latest flame, Barbara, Quincy heads off away from Los Angeles. They nearly get run off the road and then witness an accident. Quincy then finds himself in a life or death race to isolate a mysterious poison, found in the woman's body, that has already claimed two lives

A policeman is killed while on a routine visit to a house. The killer turns out to be an old friend of Sam's, the gentlest man Sam has ever known. Arrested he admits that he killed the policeman and then, while in a cell, kills himself.

Sam is determined to find out what changed his friend and investigates. He finds radiation in the jawbone and uncovers the story of a military experience in Germany that involved torture and, possibly, the force-feeding of a radioactive drug. Can Sam prove that this is what caused his friend to kill and restore his good name?

A woman, Vicki Maguire, who has suffered from agoraphobia, manages to finally leave her house, for the first time in seven years. While walking her dog along the beach beside her house she looks in through the window of another house, and witnesses what she thinks is a woman being strangled. The police are called and when Monahan and Brill get to the house there is no body, no sign of a struggle and a completely different man in residence. No one believes her story, except for her psychologist Dr. Rainer, and she goes to see Quincy. She persuades him that the woman wasn't seeing things and that he should help her find out the truth, before she suffers a relapse and will never be able to leave her house again.