Synopsis
Saya Otonashi leads an ordinary life with her adopted family in Okinawa City, appearing to be a typical high school girl. Her only unusual traits are a tendency toward anemia and a complete lack of memories from before the past year. But Saya's forgotten history resurfaces when she is attacked at school by a blood-drinking creature. A mysterious man named Haji intervenes to drive the monster away. When he forces her to drink his blood, Saya enters a trance and uses her own blood as a weapon to easily kill the beast. Saya discovers the existence of Red Shield, an organization created specifically to combat these monstrous beings. Together with Haji, she must join forces with Red Shield to battle the terrifying creatures and uncover the truth behind her lost memories.