Food critic Paul Gerard has been blackmailing gourmet restaurant owners for huge sums of money in exchange for favorable newspaper reviews. When restaurateur Vittorio Rossi threatens to expose Gerard, the dashing Frenchman plans a near-perfect crime using the deadly poison from a Japanese fish that only licensed chefs are qualified to handle. Lt. Columbo, stymied by the ingenious plot, is without a lead until Eve Plummer unknowingly gives away Gerard's expertise in handling the deadly Japanese fish.