Knives and Chains

Mizuki Tsuki has no memory of her past before Zero found her. She only remembers she was sent to that cliff with a mission in mind. If only she could knew what that mission was exactly. After Yuki left Zero has been heartbroken and hasn't seen her for the past 7 years.
Mizuki stays with Headmaster Cross and Zero since a certain someone wants her there. She doesn't want to but something is telling her to stay. At the same time she might have feelings toward Zero. But what will she do when she finds out his secret?
Will she still want to help him heal?
Or will she leave?