 Nelson Brenner, a top CIA operative, is really a double agent who finds it necessary to rid himself of a fellow spy and make it look like a mugging. Brenner inadvertently leaves tiny clues in a photo shop at a carnival, on Brenner s corpse at the beach, in a tape recording he makes while in his Agency-approved identity as a speech-writing consultant - the kind of clues that no one would ever pick up on. No one, that is, except the rumpled, redoubtable Lt. Columbo. The indefatigable detective will find himself followed by mysterious agents, visited by the top man himself and entertained with a recording of "Madame Butterfly" in Brenner s own mansion before solving this difficult case.