Hellboy (Ron Perlman) and his team face off against a new supernatural threat, while Professor Bruttenholm (Sir John Hurt) must investigate the possible reemergence of a vampire he had slain decades prior.
When an attempt on Dr. Alec Holland's life leaves him consumed by deadly chemicals and fire, the swamps of Louisiana transform him into a superhuman creature hell-bent on ridding the swamp--and the world--of the evil that men do.