Ronnin (preparatory school student) Tomoki Tatsumiya has decided to stay at his mother's family home to attend prep school.

Welcoming him were— His mother's older sister, Azumi-oba, a lawyer, and Her younger sister, Mahoro-oba, who is domestic.

A new life begins under one roof with the beautiful sisters. There's no way things will go smoothly—

"This is our little secret, okay? Don't tell Mahoro... okay? Hehe..." "This is our little secret... right? Please don't tell my sister... hehehe...♪"

Before he knew it, he was sharing "secrets" with the two of them. And every time night falls— He is led astray by his two aunts.