Nancy, along with Bess and George, find the wrech of an old yacht with a safe inside full of jewelry worth a small fortune. Cousins of the Druthers, who are clients of Nancy's dad Carson Drew owned the yacht. Their will leaves everything to Mr. Druthers, specifically excluding his spouse - but no one has seen him for ten years. The rumor is that Mrs. Druthers murdered him. Things take a surprising turn when suddenly Mr. Druthers reappears, and Mrs. Druthers disappears!