At the end of World War II, Nazi officers Karl Ruprecht Kroenen and Ilsa Haupstein start an experiment to raise the forces of Hell trough Russian dark mystic Rasputin on a Scottish island, but it's interrupted by an allied commando guided by professor Trevor "Broom" Bruttenholm. He prevents killing the human-demonic half-blood, which was accidentally created and raises this "Hellboy", while rising to head of a secret C.I.A.-linked U.S. agency Bureau of Paranormal Research, which secretly studies and uses the occult, including supernatural freaks. As "father" Broom is aging, he hand-picks brilliant, sensitive Agent John Myers as new minder-companion, as regular "warrior" Agent Clay can't empathize and lacks flexibility mental. Hellboy is quite a handful, regularly spotted by worried civilians on unauthorized excursions, especially to pyro-telekinetic freak friend in a mental asylum. Johnny, Hellboy, and Clay team up on missions against paranormal threats with aquatic-bionic freak Abe Sapien. Their task proves to be daunting, as monster Sammael multiplies every time it "dies", while Rasputin and the Nazis reemerge, armed for revenge.A demon, raised from infancy after being conjured by and rescued from the Nazis, grows up to become a defender against the forces of darkness.