A friend of Ironside's turns out to be an amnesiac victim without a past. The need to discover who she really is comes to the forefront when somebody tries to kill her, and it becomes clear that the Chief's hopes for a long term relationship might not be possible with this particular girl.

A policeman is shot and killed by an assailant. The evidence points to the murderer being a local thief, currently enjoying a reign of terror in San Francisco, but soon the investigations lead elsewhere.