In this continuation to the adventure of the demon superhero, an evil elf breaks an ancient pact between humans and creatures, as he declares war against humanity. He is on a mission to release The Golden Army, a deadly group of fighting machines that can destroy the human race. As Hell on Earth is ready to erupt, Hellboy and his crew set out to defeat the evil prince.
In the final days of World War II, the Nazis attempt to use black magic to aid their dying cause. The Allies raid the camp where the ceremony is taking place, but not before a demon - Hellboy - has already been conjured. Joining the Allied forces, Hellboy eventually grows to adulthood, serving the cause of good rather than evil.