"Kizumonogatari: Koyomi Vamp" is a three-part film series that serves as a prequel to the "Monogatari" franchise, adapting Nisio Isin's light novel of the same name. The story centers on Koyomi Araragi, a high school student who becomes entangled in supernatural events after encountering a vampire. The narrative begins with Araragi discovering the weakened form of Kiss-shot Acerola-orion Heart-under-blade, a legendary vampire also known as the "King of Apparitions." She has been dismembered and left powerless by three vampire hunters: Dramaturgy, Episode, and Guillotinecutter. Araragi, driven by a mix of curiosity and compassion, offers his blood to restore her strength, inadvertently turning himself into a vampire in the process.

As Araragi grapples with his new vampiric nature, he learns that to return to being human, he must retrieve Kiss-shot's missing limbs, which are held by the three hunters. Each hunter represents a distinct challenge: Dramaturgy, a vampire executioner, embodies brute strength; Episode, a half-vampire, wields cunning and speed; and Guillotinecutter, a human priest, relies on specialized anti-vampire weapons. Araragi's quest to reclaim Kiss-shot's limbs unfolds across the three films, with each confrontation revealing more about the hunters' motivations and the moral complexities of Araragi's situation.

Throughout the series, Araragi's interactions with Kiss-shot and his classmate Tsubasa Hanekawa provide insight into his character. Hanekawa, who becomes aware of Araragi's transformation, offers support and guidance, serving as a grounding presence amidst the chaos. Kiss-shot, on the other hand, oscillates between a regal, otherworldly demeanor and a more vulnerable, human-like state, reflecting her dual nature as both a fearsome vampire and a being capable of forming genuine connections.

The climax of the series revolves around Araragi's ultimate decision regarding Kiss-shot's fate. After reclaiming her limbs and restoring her full power, he is faced with a choice: allow her to remain a threat to humanity or sacrifice his own humanity to weaken her. The resolution underscores the themes of sacrifice, morality, and the blurred lines between heroism and self-interest. The films conclude with Araragi returning to a semi-human state, setting the stage for the events of the broader "Monogatari" series. The narrative is tightly focused, blending action, introspection, and dialogue-driven storytelling to explore the consequences of Araragi's choices and the nature of his relationships.