Mari wakes up every morning with five years missing, surrounded by girls who seem to know something about her that she doesn't. The academy isn't a school, it's a cage, and every other student in it is watching to see if she'll remember what happened when everyone else died. The show trades jump-scares for something worse: the slow, suffocating certainty that you're watching someone excavate her own trauma while forces around her wait for the moment she becomes dangerous.
Mari wakes with no memory of the catastrophe that killed everyone on Kamioki Island five years ago. She's the sole human survivor, though she can't remember why or how. Now trapped at Kaihou Academy, an elite girls' school isolated from the outside world, Mari begins to sense that her presence here is no accident. Someone is watching her, waiting for her memories to surface. What she doesn't know is far worse: she may not have been the only thing that walked away from that island alive. When a mysterious girl named Hagino transfers to the academy, Mari feels an immediate, magnetic pull toward her. But intuition screams that Hagino cannot be trusted. As strange events unfold and Mari's fractured memories begin to surface, the line between protector and threat blurs. Something inhuman wears a human face at Kaihou Academy, and Mari holds the only key to understanding what it wants. The question isn't just what happened five years ago, but whether Mari can survive learning the answer.