A most unexpected client shows up at Charlotte Holmes's doorstep: Moriarty himself, who fears that tragedy has befallen his daughter and wants Charlotte to find the truth. In this sixth outing (after Murder on Cold Street), Charlotte and Mrs. Watson travel to a remote community of occult practitioners where the girl was last seen. Charlotte has to wonder why Moriarty has entrusted this delicate matter to her—was it merely to test her skills as an investigator, or has the man of shadows trapped her in a nest of vipers?