Every year Mr. Petrusca-the best fishmonger in town-finds the biggest lobsters for one of his very best customers, Mr. Trimble. But when a thief steals the two splendid lobsters, Mr. Petrusca is more upset than anyone can understand. Hazel Green knows there's something fishy going on, but what could it be? Through clever sleuthing, guesswork, and observation, Hazel discovers that Mr. Petrusca can't read. Hazel promises not to tell anyone, and she finally solves the mystery without giving away Mr. Pertrusca's secret. But will catching the thief solve all of the problems that this fishy mystery has created?
