Himeko Hanatsuka, age 12, and Bunji Tsuchiya, age 30. Their relationship status: "engaged." This story takes place during the Taisho Era, when modern Western culture was steadily spreading in Japan.

In this unsettling and vibrant atmosphere the two, who call each other "Bunji-sama" and "Fiancée-dono", slowly develop their love surpassing the 18 year age gap.