Quiet and shy Kawai Arisa is an average 14 year old high school girl, except she is often the target of bullies as her family tend to move around a lot.
The fact that, Inogami Yuuki, the most popular student in her class, is nice to her, gives another reason for others to bully her.
One day new transfer student Yashiro Akira accuses Arisa of bullying him when they lived in the same town, but Arisa has a memory loss from five years ago, when she fell down the stairs!
Could be a bully the past?
Is there split personality, or other suppress memories may haunt her.