Ep. 1: Amnesiac student Saya Otonashi faces a vampire and chiropteran monster after a mysterious cello player saves her.

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Saya Otonashi, a high school student with no memories prior to one year ago, requires regular blood transfusions to maintain her health. After hearing a cello performance that evokes a faint memory, she returns to school at night to retrieve forgotten shoes. A man holding a dagger approaches her, causing her to flee into the arms of teacher Mr. Inamine, who is subsequently killed by a monster. Saya locks herself in a classroom, but the creature breaks through. The cello player reappears, defeats the monster, and takes Saya to safety. He reveals the creature is a chiropteran and forces Saya to drink his blood by kissing her, instructing her that she must now fight. Her brother Kai arrives after friend Kaori delivers the shoes, also encountering the monster during the incident.