It is Kyogoku’s first novel, and the first entry in his Kyōgōkudō series about atheist onmyōji Akihiko "Kyōgokudō" Chūzenji.

The Summer of the Ubume is told from the perspective of freelance writer Tatsumi Sekiguchi, who is investigating rumors of a woman at the Kuonji Clinic who has remained pregnant for twenty months after the disappearance of her husband.

He seeks advice and help from his close friend Akihiko Chuzenji, whom Sekiguchi refers to by the name of his bookstore ("Kyōgokudō").

Sekiguchi is further drawn to the case when he meets the pregnant woman's beautiful sister, Ryoko Kuonji, and she asks for his help in solving her brother-in-law's disappearance from a locked, sealed room.

With the help of his friends - Kyōgokudō, private eye Reijiro Enokizu, police detective Shujiro Kiba, and fellow reporter Atsuko Chuzenji (Kyōgokudō's sister) - Sekiguchi attempts to discover the disappearing husband's fate, but he soon learns that there is much more to the Kuonji Clinic than meets the eye, and that his own involvement with Makio Kuonji's disappearance may run deeper than he thinks.