After being shot by robbers who were holding up a store, a young police officer is treated by a doctor who was on the scene. Unfortunately, the officer later dies, and the doctor becomes the only one who can identify the robbers. But when Stone and Keller try to call him, they find that he had to be using a phony name. The man has been practicing using the name of several different doctors.

When the brother of a cop is killed along with the mobster he was working for, the young officer is assigned to work undercover as a bookie to find out who ordered the hit. Stone, who is ordered to tell no one else about the man's assignment. is concerned that the officer is too concerned with revenge to handle the job effectively.