Asa & Natsume are both in love with Hajime Saisho. Instead of fighting over him, they both promised to share him equally. However, both girls have to leave him by the end of the summer. As the summer days go by, they each spend their precious time with Hajime, while the day of their fated departure draws near.

Set in a rural town, Kouta is the only son and heir to the Mikomori shrine in the small redeveloping town of Tsumagoi-chou which had been declining in popularity. He didn’t have any interest in inheriting the shrine. Instead, he focused on his studies, aiming to be a civil servant upon graduation. His widowed father talked about marrying a young girl, but then he suddenly disappeared. That girl Erina came to live with him, along with her younger sister Motoka. With the help of his childhood friend Mio and a few supporters of the shrine, they managed to continue living normal lives. One day, Erina brought home a girl Mai, who called herself his fiancée. One thing led to another, culminating with Erina ordering him to get her pregnant.