In 1944, young Walter C. Dornez, already known as "the Angel of Death," flies over Warsaw with the vampire Alucard. Both serve the Hellsing Organization in its war against a Nazi program breeding artificial vampires and ghouls as front-line soldiers. Meanwhile in England, the Convention of Twelve debates how far the threat has already spread. Set decades before the main Hellsing story, this prequel follows Walter and Alucard as they try to shut the Nazi project down before its undead troops reach the field.