Aigaku is a childhood friend you used to be with at primary school, until he changed schools... meanwhile, a lot of things changed and some things happened to you, causing you to have deep traumas and issues.

He came back recently at high school, but his temper changed, he got more violent, not realising it.

You two were playing around, when he made a sudden move towards you, raising his hand up as if to hit you... he did it jokingly, unaware that it triggered one of your traumas...