After six CONTROL agents die in unusual circumstances insurance investigator "Ace" Weems informs Maxwell Smart and the Chief that all were former members of the team. The culprit is deemed to be Adrian Listenger, seeking revenge after being forced to drop out of the spy school because one of the team members reported that he had cheated on a test.
Little do they realize that Weems is in fact Listenger, his appearance altered by means of a self-performed nose job and a change in hairstyle.
When a body identified as Listenger (actually an anonymous wino murdered by Listenger) is found at the Senator Hotel in Washington this leaves only Max and the Chief (who had been the team's coach) on the list and they begin to suspect each other.
This is exactly what Listenger wants. He lures them to the abandoned Twin Oaks Restaurant hoping they will kill each other in the showdown but the two friends each realize that the other could never be a murderer and instead it is Listenger who falls in the ensuing shootout.