 Without a case to occupy his restive mind, Holmes breaks his ennui by agreeing to investigate the story of an amateur cartographer who stayed overnight at the rented lodge of another map enthusiast but awoke in the morning to find his host and servants mysteriously missing. Holmes finds he has a rival in the ambitious and publicity conscious Inspector Barnes, who sees himself as The Great Detective s peer and is reluctant to share information with him. When the Spaniard is found bludgeoned to death, Barnes suspects his mulatto servant, but Holmes directs his efforts in a different direction.