Mahiru goes in search of her sister who has been missing for 2 years now and meets Yukito claiming to be a bodyguard and her proxy. He warns her that her sister is probably involved in something dangerous, but she can't give up. This choice forever changes her.
(Source: MU)

There were 99 beasts were set on the world that did chaos. They were sealed within "vessels" and they choose their own "masters". Three girls found a vessel and one of them made an all-girl school. Yukiji Shinazuki goes there as a freshman. Tamakichi Shinazuki lives with her and causes chaos all around Yukiji...even at the all-girls school! What's even more surprising about Tamakichi is...read it and you will find out!