A health club owner murders one of his franchisees. Lt. Columbo is on the case. Milo Janus owns a chain of health clubs, but one of his franchisees discovers the man is cheating him - and can prove it to the authorities. Janus responds by murdering his partner and making it look as if he had accidentally killed himself trying to lift a barbell that was too heavy for him. Janus creates a would-be perfect alibi for himself involving a tape recording of his victim's voice, a phone that doesn't light up, a sexy secretary, a party for friends at his house, and a pornographic horror movie. But no alibi is perfect when the rumpled Lt. Columbo is on the case.