Plot for Doctor X: A monster lurks as a New York newspaperman investigates one of the "Moon Killer" murders in which victims are strangled, cannibalized, and surgically incised under the light of the full moon; plot for The return of Doctor X: A New York journalist finds himself out of a job when the actress that he reports as dead shows up alive and threatening to sue his newspaper; plot for Mark of the vampire: Local villagers believe a vampire is killing residents; plot for The mask of Fu Manchu: An infamous Asian mastermind and his diabolical daughter raid the tomb of Genghis Khan; plot for Mad love: An insane surgeon's obsession with an actress leads him to replace her pianist husband's wounded hands with those of a murderer; plot for The devil-doll: A Paris banker framed for robbery and murder escapes from prison with a scientist.