The episode begins with an elderly man named Mr. Matthews playing the piano. His nephew, Dale Kingston, comes in and shoots him. He then goes and gets an electric blanket to put over the body to keep it warm. Then he trashes the house and scratches up the door to make it look like the lock was picked. When he is finished, he smiles and looks around at all the paintings on the wall. He takes them down and removes them from their frames. He wraps up two of them in paper and as he is doing so, the doorbell rings. It is a woman named Tracy, who is Dale's girlfriend. He tells her to remember to take the electric blanket upstairs and to fire a shot out the window after he's gone. Then he leaves and goes to an art show.
He meets an artist there and asks him for the time. The artist tells him it's five minutes to 11.
Back at Dale's house, Tracy waits for the security guard to do a check, then fires the gun in the air. The security guard lets himself into the house, and Tracy runs out the back door, escaping in her car.
Columbo comes to the murder scene, where the medical examiner says that he puts the time of death around 11. Columbo talks to one of the servants who says that Dale was Matthews' only living relative. Columbo talks to Dale and says he's surprised that someone would go after the paintings by the less famous artists. Kingston goes to look at the two frames where the paintings that he took were. He is very upset and tells Columbo that they were worth over a half a million dollars. Columbo remarks that it's odd that the thief first went after cheaper paintings, then in the middle of everything, became smart and went after the most expensive paintings there. As he's talking, a woman named Sally comes in. Columbo takes her out back and asks the security guard to stay where he was when he came in the house. Columbo then tells Sally to run down the stairs, and the security guard says that's the noise he heard when he came in: high heels running down stone steps. Columbo says that there must have been more than one person who broke in so that someone could open the door from the inside without setting off the burglar alarm. Columbo asks how a thief would get rid of a valuable piece of art, and Kingston tells him they usually try to settle something with the insurance company or an art gallery. Columbo says that the thief might try to contact Kingston, so he will set up a tap on the phone in case. Kingston agrees to it.
Columbo then goes to see the artist that Dale met at the party the night before. The artist isn't very helpful, but the valet who parked Dale's car says that it was five to 11 when he parked. He also says that he helped Dale search his entire car for a missing cuff link, but they never found it.
Tracy calls Dale on the set of his television show. He tells her not to worry, then gets off the phone quickly when he sees Columbo approaching. Columbo tells him that because he hasn't been home much the tap isn't doing much good. Dale says that Mr. Matthews' ex-wife still is listed under her married name so maybe someone will try to contact her about the painting. Columbo says he saw her that morning and tapped her phone, too. Then he says that Dale's alibi checked out. He goes on to say that in most cases, people don't remember details like the exact time, but in this case, he knows an exact time and also that the entire car was empty. Columbo says that he stopped by Dale's apartment a few times, and Dale gets defensive. He says that Columbo can snoop around his place all he wants, but he won't find any stolen paintings. He gives Columbo the keys.
Dale meets Tracy on a deserted road, and she gives him the paintings and the gun. Tracy expressed doubt about whether Dale really loves her. He swears that he does, but as she turns her back on him, he picks up a rock and kills her with it. When he gets home, he takes the paintings out of the trunk of his car. He gets the key that Columbo left under the mat, but when he goes inside, Columbo is still there, fast asleep in a chair with a book on his lap. Columbo asks to see the paintings that Dale has with him, but Dale says he's too tired. The phone rings, and it's the police calling to tell Columbo to come to the scene where Tracy's body was found.
Columbo goes to the reading of Mr. Matthews' will. He pulls out a painting that Tracy did and shows it to Dale. He says that the dead girl was an art student, and he thought maybe he knew her. He then shows Dale a picture of her, but Dale gets annoyed and says that he can't possibly be expected to remember everyone. They go into the conference room, where the attorney tells them that the entire art collection was left to Edna. Dale shows Columbo a letter from his uncle that was sent 10 days before and told him that he had changed his will.
Columbo goes to see Tracy's landlady to see if she ever saw Dale Kingston visit Tracy. She doesn't remember him. Later, a gardener at Matthews' house finds the gun in the bushes. Columbo goes to talk to Mrs. Matthews, whose house is right down the hill from her ex-husband's house. She says that she and Mr. Matthews had become friends again since their divorce. Matthews decided that he wanted his paintings to go to museums, so he changed his will in case he died before he could decide where to send it all. Dale shows up at the house, where he learns that the gun has been found. Columbo calls the ballistics department and confirms that the gun is the murder weapon. Mrs. Matthews says she's walked up and down that hill many times, and Dale tells her not to talk about it because Columbo might get the wrong idea. Columbo assures them both that he doesn't think Mrs. Matthews had anything to do with it.
After Mrs. Matthews leaves, an officer shows Columbo the paper that was used to wrap the stolen paintings. He found it in her trash can. Dale says he's still convinced that she had nothing to do with the murder, and Columbo tells him he agrees. He says that he's going to sit on everything and wait for the paintings to show up. Dale tells him he really ought to search her house, so that he can be sure. Columbo says he doesn't think it's necessary, and he leaves.
Dale goes to see the family attorney and convinces him to get the house searched in order to prove Mrs. Matthews' innocence. The attorney agrees to try to make it happen and also to try to find a way around Columbo. Dale plants the paintings in Mrs. Matthews' car, inside a box she brought home from the shopping center, then hides them in her closet when they get to the house. A man named Captain Wyler shows up to search the house, but Columbo arrives shortly after him. Dale tries to get him to leave, but he stays. Mrs. Matthews tells him that Dale and the attorney advised her to do it.
Columbo tells them to fingerprint the paintings, then accuses Dale of murdering his uncle. Dale dares him to find a way to prove it. Columbo tells him that when he was at Dale's apartment and Dale came home with the paintings, he managed to touch them before Dale could stop him. Columbo says his own fingerprints are on the paintings. Dale says that he must have touched them just then when no one was looking, but Columbo pulls his hands out of his pockets and shows that he's wearing gloves. Dale realizes he's caught, and so does everyone else.