There is this girl named Saya who looks to be the reincarnation of a psycho girl from the past who killed pretty much everything including the monsters which had appeared back then. On her way home Saya sees a guy playing a cello (named Hagi) for a crowd which triggers some sort of flashback where she witnesses a girl trying to open something locked. A little later on as Saya’s going out her house George (her foster father), and David (some business guy), debate over who Saya essentially belongs to. To make the long sequence of events short: Saya runs back to school to get some shoes she had forgotten; she bumps into the cellist guy who’s now weilding a dagger instead of a bow…; and one of her teachers is eaten (well, mutilated) by some sort of monster hiding in a tree.
Saya runs away from all this of course, and bumps back into the cellist guy who she was scared off by in the first place. Turns out Hagi has some skills other than with a cello and he chucks the dagger into the monster’s eye. Some weird stuff follows (this series is all about weird)…Hagi has this demonic looking arm. He cuts it and implies that he wants her to drink his blood? In the end she does anyways when he forcefully kisses her. And then, the circle comes full swing. By drinking his blood she reinvokes the spiritual essence of that girl who she saw in her vision opening the lock.