Plot
Part One
The comic opens in 1944 with a report from U.S. Army commander George Whitman, who has been ordered to lead a team of commandos to the (fictional) village of East Bromwich in the English Midlands. The army group (accompanied by a Nazi-fighting superhero called The Torch of Liberty) is under the guidance of three members of the "British Paranormal Society", one of whom is a young Trevor Bruttenholm. According to the medium Lady Cynthia Eden-Jones, a terrible event is to take place in the ruins of a nearby church: an occult ritual conducted by agents of Nazi Germany, which could herald the end of the world.
However, the actual rite is taking place at "Tarmagant Island", a small landmass off the coast of Scotland. The Nazis have set up an array of strange machines around a stone circle, in the center of which stands the fabled Russian mystic Grigori Rasputin. Armed with a pair of powerful gauntlets, Rasputin attempts to summon the seven gods of chaos known as the Ogdru Jahad from their extradimensional prisons to Earth. Although unseen, the Jahad are referred to as "knowing no care" and "heralds of pestilence", marking them out as amoral, dangerous entities.
The ritual seemingly fails and nothing happens; however, a boy-like, red-skinned demon suddenly appears at the church in East Bromwich and is soon dubbed "Hellboy" by Bruttenholm. Whilst the leader of the Nazi operation, Klaus Werner von Krupt, is dismayed at Rasputin's apparent lack of success, the latter knows otherwise and proclaims he has set into motion the world's ending.
The scene then changes to 1994, at the headquarters of the Bureau for Paranormal Research and Defense in Connecticut. An elderly Bruttenholm is recounting the incident of Hellboy's "birth", when the demon, now fully grown, enters his office. It is revealed that Bruttenholm has been missing for two years, having disappeared while embarking on a polar expedition. He tells Hellboy of how he traversed the Arctic Circle with "the three Cavendish boys", and a man named Sven Olafssen, who is a "renowned Arctic explorer". The quartet were led to a remote cave, which bore a strange Lovecraftian statue of a tentacled creature, and a human meditating at its feet. The last thing Bruttenholm remembers is touching the relic before he passed out. Before he can continue, he is interrupted by a plague of frogs, and runs from the office, giving his adopted son the final words of "Save yourself!".
Before Hellboy can react, Bruttenholm is killed by a huge amphibioid monster, leaving him with hole-like markings around his dried-out corpse. The creature attempts to kill Hellboy, but he proves too strong for the frog-monster and is able to shoot it dead as it attempts to escape. After killing the creature, Hellboy telephones his superior Tom Manning, informing him of Bruttenholm's death. As Manning convenes a meeting to discuss the Bureau's future, the scene changes to the interior of an old Victorian house, whilst a dark, shadowed figure discusses Bruttenholm's death with a stately old woman. As the comic ends, a frog is seen in her teacup...
Part Two
Having discovered some clues pertaining to the death of the Professor, Hellboy journeys to Cavendish Hall, a remote estate built atop a lake, along with his colleagues Liz Sherman and Abe Sapien. The owner, Lady Emma, is recognizable as the woman from the end of the previous chapter.
Lady Emma explains that she is the final heir of Cavendish Hall, her three sons having apparently died on their expedition with Bruttenholm. She also notes that her sons had not been the first males of the Cavendish line to try to find the cave; every male Cavendish for nine generations has died trying to find it. The practice began with her ancestor Elihu Cavendish, a prosperous whaler who had travelled the world and heard exotic stories in numerous ports. He had vanished during a failed attempt to find a "temple" deep in the Arctic, and since then his descendants have been cursed to repeat his folly.
Lady Emma finishes her tale by admitting that she hopes the Cavendish curse will die with her, and that Cavendish Hall will sink into the mud beneath it. The butler then escorts the trio to their separate rooms. With Lady Cavendish alone, the shadowy figure returns and thanks her for luring in his quarry. As promised, he agrees to reunite the old woman with her two surviving sons, telling them to emerge with the line "Children, come and kiss your mother goodnight..."
Deciding to begin their investigation, Abe removes his disguise and dives out of the window, hoping to find something in the watery depths below the house. Hellboy then calls Liz on an internal line, and they discuss how the butler looked exactly like Sven Olafssen, the Arctic explorer who had supposedly died during the expedition with Bruttenholm and the Cavendish brothers. A group of frogs suddenly appear in Liz's room, and when she mentions this to Hellboy, he yells at her to get out of the room immediately. When he arrives, he can find only her discarded coat and half-finished cigarette.
Olafssen is in the hall, feigning ignorance as to where Liz has vanished. When Hellboy grabs him by the collar, the man instantly transforms into a frog-monster, and the two fight through the house. After seemingly killing Olafsson, Hellboy returns to the sitting room and finds Lady Cavendish dead, covered in markings similar to those which adorned Bruttenholm's dead body. He regrets not having done something to protect her, but the dark individual seen earlier emerges and reveals himself to be Rasputin. Reunited with Hellboy, he explains that it was he who summoned the demon from the void, and that his true purpose will be revealed soon. Before he can retreat, a set of large tentacles smash through the floorboards and drag Hellboy to the cavernous depths below the house.
Part Three
In the darkness beneath Cavendish Hall —which is revealed to be an Aztec-era temple— Rasputin begins lecturing Hellboy on the nature of the Ogdru Jahad. Hellboy quickly becomes impatient and shoots Rasputin in the head, but the mystic quickly heals and overpowers him in mere seconds with a single incantation. This worries the demon, as this means his cadre of charms, amulets, relics, etc. are no use against Rasputin's power. The mystic states that Hellboy is his slave, and that he will be punished for attacking him. The transformed Olafssen then comes to his master's aid and fights Hellboy with greater strength.
Meanwhile, Abe has ventured through the waterways which connect the cellars and caverns of Cavendish Hall to the lake. In the caves, he comes across the two remaining Cavendish brothers, who have also been transformed into Rasputin's frog-monsters; however, they are not as violent as Olafssen, and are instead seen embracing the corpse of their mother before purposefully drowning themselves. Venturing further, Abe discovers the well-preserved remains of Elihu Cavendish, kept on a throne-like chair and bearing a harpoon in his hand.
As Hellboy is beaten down, Rasputin explains his origins. Having been murdered by a group of nobles in 1916 and his body flung into the River Neva, Rasputin was resurrected and empowered by the Ogdru Jahad. He took refuge in an Italian village, where his new powers made him well-known and brought him to the attention of Heinrich Himmler, who invited him to take charge of one of Hitler's various desperate "Doomsday Projects". Although Rasputin knew Hitler was doomed to failure, he also knew he could use the money, scientific minds, and technological resources of the Third Reich to broaden his ambitions. He aligned himself with Karl Ruprecht Kroenen, Ilsa Haupstein, Leopold Kurtz, and others, designing a machine that would bring the Ogdru Jahad to earth and burn it to cinders.
When the project failed and the group disbanded, Rasputin made his way north to the Arctic Circle after receiving a vision from Sadu Hem (the statue-creature found by Bruttenholm, which was now in the temple beneath Cavendish Hall). There, he was placed in a magical form of suspended animation. After being re-awoken by Bruttenholm's touch, he took possession of the expedition members and read their minds, learning of Hellboy's existence. Realizing that he could now complete the summoning ritual properly, Rasputin turned Olafssen and the Cavendish men into frog-monsters to serve him. He then psychically instructed Bruttenholm to take the relic back to America and arranged his death to lure in Hellboy.
Rasputin then reveals he had Olafssen capture Liz, as her power exceeds even that of Hellboy himself, and to use his own body as a conduit for Sadu Hem, who will in turn use this energy to shatter the crystal cocoons of the Ogdru Jahad. Declaring that Hellboy is now useless to him, the mad monk declares that, at last, the world will end.
Part Four
As Liz's power flows into Sadu Hem, the Ogdru Jahad are seen rumbling in their prisons. An unknown alien race is seen observing the events, fearing that "The Seven" will devour the universe once they have blackened the Earth. Hellboy continues to battle with Olafssen, before taking the pin from a concussion grenade and forcing it down his throat, apologizing to whatever little human sense remains in the creature.
Rasputin fails to notice, as he gleefully recites the spell used fifty years earlier to bring forth the Ogdru Jahad. Suddenly, he is speared through the chest by Abe, who is under the possession of a vengeful Elihu Cavendish. With the mystic's concentration broken, Liz's power becomes uncontrollable, reducing Sadu Hem to ash and causing the temple to collapse. His vengeance fulfilled, Elihu passes on to the afterlife, freeing Abe to save Liz. Hellboy tells him to get her to safety, because he has something to finish.
A furious Rasputin swears to kill Hellboy, but with his connection to the Ogdru Jahad severed, the mad monk's body begins to disintegrate. He tries to blackmail the demon to save his life, saying that without his knowledge, he will never "understand the power inside him". Deciding that he can live with that, Hellboy crushes Rasputin's decaying head and escapes just as Cavendish Hall sinks below the water. Abe and Liz quiz him on what happened, but Hellboy dismisses their questions. As Hellboy recalls the last words of Rasputin, the scene changes to an abandoned castle in Norway, which bears the ruins of an old, esoteric Nazi laboratory. The figures of Kroenen, Ilsa and Kurtz — Rasputin's old disciples — are seen frozen into the wall in a thick sheet of ice. However, a nearby device blinks into life, and the ice begins to crack...
