Nick and Nora Charles are attending a charity benefit aboard a gambling ship. The festive atmosphere conceals many tensions among those connected with the ship, with most of the friction centering around Tommy Drake, its unpopular, spiteful band-leader. When he is murdered later that night, suspicion falls on Phil Brant, who had argued with Drake earlier in the evening. When Phil and his wife seek help from Nick and Nora, Nick refuses to get involved. But when shots are fired outside his own apartment, Nick begins to investigate, and he soon finds himself in a confusing case with numerous suspects.