In a countryside setting, Kouta is the sole son and designated successor of the Mikomori shrine located in the village of Tsumagoi-chou, which has seen a decline in prominence. He shows no desire to take over the shrine; instead he devotes himself to academics, hoping to become a civil servant after graduation. His single father discussed marrying off his son to a young woman, but then vanished abruptly. That woman, Erina, moved in with him together with her younger sister Motoka. With assistance from his childhood companion Mio and several shrine supporters, they maintained ordinary lives. Despite the challenges, Kouta remained determined to follow his own path. One day Erina brought home a girl named Mai, claiming to be his fiancée. Eventually, Erina demanded that he conceive her child.
