It’s certainly among Sidney Toler’s more energetic portrayals of the detective. The story involves him and his loyal assistant, Jimmy (Victor Sen Yung), getting caught up in a quest for buried riches on a vessel that remains stationary. Ethel Griffies plays "Patience Nodbury," who claims to be related to the notorious pirate “Black Hook,” and possesses a map detailing the treasure’s location. To protect it from theft, she cleverly splits the map into four parts, distributing them among the other travelers onboard. Conveniently, the appearance of a character resembling "Long John Silver"—complete with a wooden leg—causes an elderly woman to collapse, triggering a competition to recover the map fragments and identify the killer before anyone else meets their end. The film is enjoyable; there’s a good amount of activity, silly diversions, ineffective police officers, and a briskly moving plot that keeps things entertaining throughout the runtime. A "Captain Flint" also makes an appearance.

Source on TMDB