Hellsing, an organization specializing in dealing with supernatural threats, is called in to eliminate a vampire that is turning the villagers of Cheddar into ghouls. To put an end to this, the leader of the organization, Sir Integra Fairbrook Wingates Hellsing, dispatches her most formidable asset: a powerful vampire known as Alucard. Armed with only a single handgun, Alucard wreaks havoc on the monsters plaguing Cheddar. However, a young police officer, Seras Victoria, gets caught up in the chaos and becomes mortally wounded as a result. Taking pity on the girl, Alucard gives her a choice: die as a human or live on as a vampire. Seras accepts his offer and begins a new life as a member of Hellsing. Though it was her decision, Seras struggles with the fact that she is no longer human. Nevertheless, she must embrace being a creature of the night soon if she wants to survive on the front lines in the fight between humans and the supernatural.

Youto Yokodera wants to be seen in a way different from most men: as a pervert. However, his lewd actions are often misinterpreted as good intentions, and people cannot see his true nature. Upon hearing rumors of a cat statue that can banish an unwanted trait, he searches for it and prays for his façade to be removed. But each wish comes at a price: those unwelcomed traits are transferred to someone else who desires them! After realizing that vocalizing his dirty thoughts is not the best thing, Youto decides to regain his lost traits by seeking out the person who received them. Unfortunately, he was not alone in praying to the cat statue, and now he must not only fix his life, but the lives of others as well.

Now there's a mysterious Mask before James Blood, and the man behind it is one that shouldn't exist. What is the mystery surrounding this mask...? So begins an action-packed crime story set in a beautiful city!

When a gust of wind blows away a young woman's hat, a high school girl sprints past her and leaps into the air to retrieve it. However, this is no ordinary girl. Feeling the hat barely escape her grasp, the girl morphs her body into a fighter jet, blasting off into the distance with a burst of speed to catch it. This encounter is the young woman's unexpected introduction to the Henkei Shoujo: seemingly normal girls with incredible transformation powers who live among humans.