It sounded like a good idea …

Offer passengers elite classes in diet, health, and exercise.
Persuade world-renowned experts to teach the seminars.
Book them on the Pegasus—a luxurious cruise ship sailing from Florida to Alaska.

That was the thought of Collin Woodward, the Vice President of Flagship Cruise Line, when he invited aboard:
Clifford Freeman, the mesmerizing hypnotherapist
Kenna Chavasse, the seductive light-food chef
Jean Claude Regale, the mysterious Olympic star
Rita Diamond, the free-spirited diet expert
Dr. Marco Renato, the erudite psychiatrist and
Deidre Lovejoy, the hot-tempered TV talk-show hostess and his fourth wife.

The timing of this cruise couldn’t have been better for Alec DunBarton, The Singing Sleuth. After serving three months on the Pegasus, he had managed to gain thirty-five pounds by eating six fattening meals a day, drinking double Scotches, and avoiding all exercise.

Just as Alec finds a weight-loss plan that seems promising, one of the guest speakers is killed in the ship’s sauna. Even though homicide is a nasty business, Alec is more certain that
“Losing Weight is Murder!”