Present

Twenty-seven years after Daysdeath, a mysterious phenomenon that has cast the world into perpetual darkness, vampires have successfully conquered humanity. Gabriel de Leon, the last living vampire hunter, is held prisoner awaiting execution for killing the Forever King, Fabien Voss. However, Margot Chastain, the new vampire Empress, orders Gabriel to tell her personal historian, Jean-Francois Chastain, his entire life story before he is executed.

Twenty Years Previous

At thirteen, Gabriel encountered his first vampire when his younger sister and her friend vanished, returning days later as "wretched" (feral, zombie-like vampires that revive after decomposition has set in). He manages to fight the creatures off long enough for other villagers to help kill the vampires. When he was fifteen, he succumbs to a sudden bloodlust and bites a girl to drink her blood, causing a panic. Before a lynch mob could kill him, members of the Order of San Michon (a monastic Order of vampire hunters, colloquially known as "Silversaints") arrive, save and take Gabriel into their custody, and reveal his true father was a vampire. He is recruited into the Order and trained under veteran Silversaint Greyhand.

He learns that there are four vampire bloodlines (Ilon, Chastain, Dyvok and Voss); each possesses a unique ability or 'bloodgift', but he has none, making him a "frailblood." While hunting a vampire plaguing nearby villages, Gabe discovers his bloodgift is sanguimancy (blood magic), meaning his father was of the fifth, presumed extinct, vampire bloodline (Esani). Seeking to learn more about his heritage, Gabriel sneaks into the forbidden section of the Order's library where he encounters two novices, Astrid Rennier, the emperor's bastard daughter, and Chloe Sauvage, researching what caused Daysdeath and how to end it. The three of them begin meeting secretly in the library to research both Daysdeath and the Esani bloodline, eventually learning only the Holy Grail can end Daysdeath.

Eventually, Gabriel, Greyhand and several other silversaints are sent on a hunt after Laure Voss, the Forever King's favorite daughter, scouting paths for her father's invasion of the empire. She cripples Greyhand, but Gabriel manages to wound her, save his fellow Silversaints and intercept her message to her father. The Silversaints march to defend the route the message claims the Forever King plans to invade by, while Gabriel is forced to stay behind due to insubordination. However, he discovers secret writing in Laure's message indicating the vampires will actually invade via an unguarded mountain pass. Gabriel gathers all the nuns, monks, and blacksmiths in service to the Silversaints to stop the vampires. During the battle, Laure taunts Gabriel with the knowledge she destroyed his village and killed his family; enraged, Gabriel slays her using his bloodgift while his comrades trigger an avalanche that destroys the approaching vampire army. Before retreating, Fabien Voss swears revenge for the defeat and his daughter's death. For slaying Laure, Gabriel is initiated into the Order and knighted by the empress for stopping the invasion. For the next five years, Gabriel becomes the greatest of the Silversaints and a hero to the people. However, he and Astrid concurrently stay as lovers over the years, resulting in their expulsion from the Order when she becomes pregnant.

Three Years Previous

After eleven years of being exiled, an older and bitter Gabriel comes out of retirement. While travelling he meets the Company of the Grail led by Chloe Sauvage, who has found a young urchin named Dior Lanchance who is the Holy Grail; as a direct descendant of the Redeemer, her blood can destroy vampires and heal injuries. They are quickly pursued by Danton Voss, the Forever King's youngest son and best hunter, and a mysterious masked vampire of the Esani bloodline called Liathe, both of whom want the Holy Grail. Danton catches up to them at an abandoned monastery and kills the Company of the Grail, but Gabriel and Dior escape him by jumping off a cliff into a river.

Dior reveals that she discovered her powers as a young orphan when she and a friend tried to kill a bishop for molesting children, and Chloe saved her from being executed for witchcraft and heresy. Gabriel in turn reveals that after being excommunicated, he and Astrid married and had a daughter named Patience. For over a decade, they lived happily as a family, until Fabien Voss arrived at their home. Seeking revenge for Laure, he murdered Patience, turned Astrid into a vampire and left Gabriel for dead in a shallow grave. Gabriel survived and swore to kill Fabien and his entire bloodline in retaliation for his family's deaths.

After escaping Inquisition agents hunting Dior, they find refuge in a town protected by two Silversaint comrades of Gabriel's, but a pack of vampires led by Danton arrive and threaten to destroy the town unless Dior is surrendered to them. Dior flees to avoid risking innocent lives, but Gabriel and Danton both pursue her. In the ensuing battle, Liathe arrives and slays the other vampires, while Gabriel duels Danton until Dior stabs the distracted vampire in the back with a sword smeared with her blood, destroying him.

Finally reaching the Silersaints' monastery, Gabriel discovers the Silversaints intend to sacrifice Dior to end Daysdeath. Gabe tries to stop them, but his former brothers slit his throat and throw him into a chasm. Liathe saves and heals Gabriel, revealing she is his half-sister Celene Castia; turned into a vampire by Laure when she destroyed their village. With Liathe's help, Gabriel returns to the monastery to save Dior, killing several Silversaints, including his old mentor Greyhand, in the process.

Present

The vampire historian, Jean-François, has filled up his tome and must leave for the day. Gabe tries to kill Jean-Francois, but he is saved by his thrall. Gabe continues to wait in his cell for him to return and tell the rest of his tale, while also thinking about his failures.