Plot

Friday and Gannon are working the day watch out of homicide when they respond to a late night call at the house of Jessie Gaynor. Her daughter Nora Hamlin is staying with her due to a separation from her husband. The call involves a gunshot heard from a locked study where Carl Hamlin's body is discovered. It is assumed at first that he killed himself but when Ray Murray from SID tells them that the bullet doesn't match the gun it turns into a murder case.—tomtrekp

Friday and Gannon, working out of Homicide, get a call from the house of Jessie Gaynor, whose daughter Nora Hamlin is staying there following her divorce from her husband Carl. Carl had stormed into the house waving a gun and threatening to kill himself. He's now locked himself into the study room and Friday must break the window to get in.

When he and Gannon finally get into the room they find a chair butted against the locked door and also the body of Carl Hamlin, bearing a .38 Colt revolver with one round fired. Uniformed police arrive to try and revive him but he is already dead. The distraught Nora is taken out of the room and she and her mother Jessie describe the incident before Carl locked himself into the study.

After Friday and Gannon fill out the Dead Body Report at headquarters the case appears open and shut, but the next day Ray Murray of SID calls them to report that he's gotten the slug from Hamlin's body and test-fired the revolver to check against unsolved murders using .38 Colts. The rounds, however, not only don't match, but the round that killed Hamlin - a 9 mm Lugar automatic round - cannot be fired from the gun Hamlin was carrying.

Friday, Gannon, and Murray now return to the Gaynor house and search the study, but the study is secure from any outside entry. The three policemen now focus on finding the spent casing of the 9 mm since it would have been ejected from the gun upon firing. Gannon notices the rug in the study appears to have been vacuumed, a suspicion confirmed by Nora Hamlin as she had innocently cleaned the house that morning. A search of the vacuum turns up the 9 mm shell casing and Nora becomes confused when the officers tell her that her husband could not have killed himself. It is then that the truth about the incident comes when Jessie Gaynor talks to the officers again.