Integra Hellsing takes command of a small Hellsing unit in Cheddar after reports of people in the village going missing by a seemingly normal priest reaches the authorities. After D11 teams were deployed to investigate with several deaths, Alucard is deployed. Seras Victoria, a female D11 operator, is fighting her ex-D11 colleagues that turned into zombies after getting into a previous fight with ghouls. Alucard eliminates the ghouls and the priest, who was the vampire, when Seras was wounded in the gunfight. Alucard turns her into a vampire after he bites her neck to save her life.

Seras' new life in the Hellsing organization is a bit tough. Having been counted as 'lost' at the Cheddar incident, she now serves for a group dedicated to the eradication of vampires. Though she seems to have trouble adjusting, many are tolerant of her, and her new life, though the tolerance only goes so far. And she'll soon have a chance to prove herself, when a new threat is discovered, in the form of Rafe and Jessica. The two lovers are having a lot of fun! Killing families, using their blood to write obscenities and blasphemy on the wall - it's all good fun. That is, until their actions catch the eye of Hellsing, and particularly Arucard, who has no tolerance for the 'low-class' vampires. Seras' chance to prove herself becomes apparent when she's ordered to shoot Jessica, though she hesitates - Jessica's only a young girl. Would killing her make her any better, or make her worse than the monsters Hellsing hunts?

Something odd is happening - vampires seem to be growing in number. And when an Italian college student is found to have a computer chip, which has apparently made him into an 'artificial' vampire, it raises more than a few eyebrows. Even though the chip is removed, the student revives, killing many on his search for his lover, who he was caught in the act of making one of his own. Hellsing moves to put a stop to this, but there seems to be more than one person interested in the boy. Hellsing's agents are killed, and Seras is severely wounded. Not by the student, but by a man called Alexander Anderson, a member of the Vatican's section 13 - the Iscariot organization. Though having the same mission as Hellsing, the two organizations are sworn enemies, and when Arucard shows up, a heated battle takes place. One would think a human would be no match for the likes of a vampire, Anderson proves to have more than one trick up his sleeve.

The Hellsing Organization sets out to investigate a series of ""snuff films"" floating about the Internet, after footage of one of their own being killed begins to make the rounds. Meanwhile, Seras deploys with her unit, now under the command of a former SAS officer who seem to have a particularly distasteful attitude towards her, to silence an apartment building crawling with ghouls. As the raid unfolds, the secrecy surrounding the very existence of the Hellsing Organization is thrown in jeopardy when a mole broadcasts footage of the assault on live television. Seeking answers, Seras sets out on her own to investigate the scene of the previous night's raid for clues about what transpired. During her investigation, she manages to uncover clues about the origin of the snuff films and goes to put a stop to it. Seras isn't the only one on the trail, as Arucard and the Hellsing Organization are also on the scene to attend to the vicious vampire behind the camera, and the TV investigative rep

Seras is still having a hard time dealing with the fact that she's a vampire, but is slowly adapting. However, the real bad news is the violent and crazy Valentine Brothers who decide to take out the Hellsing crew once and for all by means of infiltrating their headquarters with their Ghoul Army.