In the year 1795, Dr. Victor Frankenstein embarks on a daring experiment that results in the creation of a monster by assembling parts from various corpses and reanimating them through a scientific process. When Frankenstein sees the horrifying result of his work, he is overcome with horror and seeks to destroy his creation. Despite his efforts, the creature, which he later names Adam, survives and sets off a tragic chain of events that lead to the murder of his wife, Elizabeth. Driven by grief and guilt, Frankenstein chases Adam to the icy wilderness of the Arctic, where he succumbs to the freezing cold, leaving Adam alone.
The creature, now burdened by the loss and its own existence, returns to Frankenstein’s home to bury his creator. However, it is ambushed by demons, and just when all hope seems lost, it is rescued by two mystical beings, Ophir and Keziah, who are gargoyles. These gargoyles bring Adam to a cathedral, where he meets the proud Leonore, the incredible queen of the gargoyles, and her second-in-command, Gideon. Leonore explains that they were created by the Archangel Michael to battle demons and protect humankind. She christens the creature "Adam" and offers him the chance to join their cause, but he chooses to decline, feeling he must forge his own path.
Leonore equips Adam with baton-like weapons engraved with the symbol of the Gargoyle Order. These weapons grant him the power to "descend" demons — destroying their physical form and trapping their spirits in Hell. From then on, Adam operates as a lone guardian, living in solitude for over 200 years. During this time, he actively hunts and kills demons that pursue him, always hiding from any threat.
As centuries pass, Adam makes a decision to re-engage with society in modern times, confronting a formidable group of demons. The encounter turns violent, resulting in the death of a police officer, which prompts Adam to be summoned back to the gargoyle community to face punishment. His exile is short-lived, however, as a demon, Helek, who survived Adam's previous attack, informs his master, the demon prince Naberius, of Adam’s resurrection. Naberius, who is cleverly disguised as a wealthy businessman named Charles Wessex, enlists scientists Terra Wade and Carl Avery in experiments to bring the dead back to life.
Naberius dispatches a team of demons led by his most powerful warrior, Zuriel, to attack the gargoyle cathedral and capture Adam. During the assault, many gargoyles, including Ophir and Keziah, are "ascended" and return to Heaven, while others are slain. Zuriel manages to kidnap Leonore and take her to an abandoned theater. Adam, interrogating a captured demon, learns that the demons aimed to trap the gargoyles into a trade: Adam for Leonore. Despite the threat, Adam escapes, and the gargoyles attempt to trade Frankenstein's journal—found on Doctor Victor Frankenstein's body—for Leonore.
The journal, containing secrets about reanimation, is handed over to Zuriel, but Adam follows him to the Wessex Institute, where he uncovers a sinister plot. Naberius intends to harness the power of reanimated corpses to create an army of demonic hosts capable of devastating humanity. He plans to resurrect Frankenstein’s experiments on a massive scale, reanimating countless dead bodies underground. Adam retrieves the journal, seeking help from Terra, and escapes a brutal attack by Zuriel.
He then awakens to the full scope of Naberius' plans: the demon prince’s goal is to merge the powers of the reanimated dead and demons to obliterate mankind. Adam fights his way back into the institute to rescue Terra, who has been kidnapped and is being forced to activate the reanimation process. Naberius attempts to possess Adam with a demon spirit, but the creature’s developing soul resists — demonstrating its unique nature. In a decisive act, Adam carves the Gargoyle Order's symbol onto Naberius, sending him into hell. The collapsing institute marks the climax of their battle, destroying the demonic army and ending Naberius' plans.
In the aftermath, Leonore rescues Adam and Terra from falling into the abyss, and they return to the cathedral. Leonore forgives Adam for the death of Gideon, his loyal gargoyle companion. As the story concludes, Adam bids farewell to Terra, acknowledging that his mission isn’t over, and he vows to continue defending the world from demonic threats. He narrates with conviction, "I will continue to stand as Frankenstein, a guardian of humanity," signaling his new identity and purpose. Despite the darkness he faces, Adam remains steadfast in his resolve to protect humankind from the eternal threat of demons.
