Cardiac surgeon Dr. Barry Mayfield and Dr. Edmund Hiedemann have pioneered a major medical breakthrough that Mayfield wants to publish about immediately, but Hiedemann wants to wait and do more tests. When Dr. Hiedemann's heart condition worsens, requiring the insertion of a heart valve, Mayfield performs the surgery using non-permanent sutures, that will kill his partner when it dissolves in his body. Nurse Sharon Martin, a friend of Hiedemann, who has never trusted or liked Mayfield, uncovers a suspicious piece of suture, which she takes with her from the operating room. Mayfield observes her doing this and later kills Martin in the hospital garage parking area, staging it as an apparent mugging. He later tries to pin the crime on her ex-boyfriend, a former drug addict, whom he kills as well. This episode contains one of the rare occasions when Columbo loses (or appears to lose) his temper; suddenly slamming a coffee pot down onto Mayfield's desk he angrily warns him that if Hiedemann dies, the police will have his body autopsied to check what sutures were used in his operation. Final clue/twist: Mayfield operates on Heidemann again, ostensibly for medical reasons but actually to replace the dissolving sutures. As soon as the procedure is completed, police swarm the operating suite and search for the removed sutures. Mayfield loses his composure, demanding to be allowed to leave the operating room and shoving Columbo in the process. Just as it seems that no sutures are to be found and that Mayfield is in the clear, Columbo re- enters the doctor's office and reveals that he was puzzled as to why Mayfield, always so calm and collected, would have shoved him, then realized that Mayfield used the scuffle to rid himself of the sutures. Here, Columbo pulls the sutures from the pocket of the surgical scrubs he, Columbo himself, had worn in the operating room - "the only thing not searched". The hitherto impassive Mayfield shows the first signs of distress. Nita Talbot plays Marsha, Sharon Martin's roommate. Apart from season 10's "No Time to Die", which had no murderer and is a vast divergence from the series formula, this is the only Columbo episode in which a murderer fails to kill his intended target. Directed by: Hy Averback. Story by: Shirl Hendryx.