Plot

An advertisement expert uses subliminal cues to help him commit a murder. Lt. Columbo is on the case.

Dr. Bart Keppel has a very high opinion of himself. Notwithstanding that opinion, he is being fired by Vic Norris, so Bart plans a murder, constructing a perfect alibi for himself while building evidence against the victim's wife. He kills Vic while running commentary on a promotional short film; but, even in the most perfect planning, there are bound to be some failures, and you can be sure that Lt. Columbo will find them out.—Baldinotto da Pistoia

Dr. Bart Keppel styles himself as a "motivation research specialist." It's true he has written several books on marketing and made a name for himself on the subject of "subliminal advertising," which involves inserting frames of an advertised product into the reels of a film - the frames go by too fast for the conscious mind to note them, but the mind picks them up subconsciously and makes the viewer crave what is pictured - but this advertising expert's more lucrative sideline is blackmail. He takes secret pictures of his married clients with a girl hired to tempt them. His latest victim, Vic Norris, balks and wants to turn in Dr. Keppel (don't call him "Mr." Keppel) to the D.A. The blackmailer prevents this by murdering Norris during a screening of a promotional film. Though he devises a clever alibi and an even cleverer way of tempting his victim into the wrong place at the wrong time, his projectionist finds out and blackmails the blackmailer. It's up to our rumpled Lt. Columbo to use subliminal tricks of his own to expose the killer.—J. Spurlin

Dr. Bart Keppel develops an intricate plot to kill Vic Norris. Keppel specializes in motivational research and sales promotion and had arranged to show his latest promotional film to a small group of people that includes Norris. While supposedly narrating the film "live" from behind a curtain, he uses a prerecorded narration while waiting for Norris to step out to get a drink of water whereby he can then shoot him. He knew Norris would do so, as he had fed him salty caviar before the showing and then inserted subliminal messaging into his film to heighten his thirst. He further tries to blame Norris' wife for the crime, but Keppel must act fast when an employee catches on to his scheme. As for Lt. Columbo, he suspects Keppel is responsible and uses his own subliminal messaging techniques to trap him.—garykmcd

An advertising executive kills one of his most important clients after the latter refuses to take part in the executive's extortion ring, but when his main projectionist catches on to the scheme and tries to blackmail him, the executive kills him.