With his parents working and often away, Ryota Natsukawa was busy taking care of his younger sisters and doing housework, but now that he's going to university, he's finally able to live on his own! - But then, by chance, she ends up living with his childhood friend, Kazuhito Tanaka. Kazuhito has a good appearance and personality, but for some reason he doesn't have a girlfriend. Natsukawa goes along with him to find the cause, but he can't find anything to complain about, and is thrilled by Kazuhito's kind words and deeds. She even went so far as to say, "I wouldn't do this to her"...! ? A cohabiting life where they are conscious of each other begins...!