Hellboy (Ron Perlman), his pyrokinetic girlfriend, Liz (Selma Blair), and aquatic empath, Abe Sapien (Doug Jones), face their biggest battle when an underworld prince (Luke Goss) plans to reclaim Earth for his magical kindred. Tired of living in the shadow of humans, Prince Nuada tries to awaken an ancient army of killing machines to clear the way for fantasy creatures to roam free. Only Hellboy can stop the dark prince and prevent humanity's annihilation.