At the end of World War II, in order to reverse the situation, the defeated German army actually found an evil wizard, trying to use him to summon Hellboy and defeat the Allies. Fortunately, the Allied commandos arrived in time during their ceremony and successfully defeated their conspiracy, but at this time, Hellboy, a baby, had been summoned, and the Allies had to adopt him. Professor Broome (John Hurt) is the adoptive father of Hellboy (Ron Perlman). He teaches the Baron with his kindness, and the Baron uses his incomparable body and superb skills to complete a number of special tasks for the US government. However, the dark and evil nature has always been hidden in the Baron's heart. In the end, can the kindness of mankind defeat the evil from hell?