A high schooler finds a vampire torn to pieces and decides to save her, not knowing what that choice costs him. Shaft transforms a question nobody asks, why would you help something that preys on humans?, into something that rewires your understanding of what monogatari actually is. By the time you understand what Koyomi became, the film has already shown you why he had to.
Spring break arrives, and high school student Koyomi Araragi stumbles upon a wounded figure in the darkness: Kiss-shot Acerola-orion Heart-under-blade, a legendary vampire stripped of her limbs and bleeding out on empty pavement. Most would flee in horror. Koyomi sees something else entirely. When she begs for salvation, he offers the only thing he has: his blood. The price of that mercy transforms him into a vampire. Now bound to Kiss-shot by blood and circumstance, Koyomi must navigate a new existence as an inhuman predator. The world around him shifts into sharper focus, revealing layers of supernatural danger he never knew existed. Apparitions stalk the shadows. Other supernatural beings circle closer, drawn to the scent of a fresh vampire. Koyomi wants nothing more than to reverse what he's become, but salvation isn't simple when you've already crossed into the monstrous. A visceral origin story about sacrifice, monstrosity, and the terrible price of compassion, rendered in gorgeous, unsettling detail.