The Master of Darkness demonstrates that "crime does not pay" in two macabre mysteries by Walter B. Gibson. First, a secret treasure map and a strange ebony casket hold the secret to a hidden fortune, but will it be claimed by its rightful heirs or the underworld crimelord known as "The Creeper"? Then, "Death's Masquerade" threatens the masked revelers of the Pageant of Progress unless The Shadow can unmask a serial murderer!