Yunoki Mio serves as student council chairman. With childhood friend Ayukawa Rinka, cousin Ikoma Yui and Asahina. Good times is spent busily. Parents act around foreign countries, it is hardly in the house, because there is a maid Toya Kanna it is not lonely. It loves with Kanna like sisters each other, the relation like the family.
But one day unexpected misfortune befell such her.