Tom Sawyer, Detective is a mystery story involving stolen diamonds and a twin brother, long since presumed dead. The twin, named Jake Dunlap, is a burglar who has escaped prison years ago and has recently teamed up with two more of his kind to steal two diamonds worth many thousands of dollars. During their treacherous dealings with each other, Jake has stolen the diamonds from his partners in a surprising way. The two bilked thieves are now in pursuit of Jake and are bent on killing him and recovering the diamonds.