Riri is the daughter of the upper-class Nanatsumori family, and Takuto is a servant who has served them since childhood. Having known each other since they were young, Riri and Takuto harbor deep feelings for one another, but they keep their love hidden due to the difference in their social status. One day, a military draft order arrives for Atsushi, the eldest son of the Nanatsumori family. Their father, Tokuji, an officer, is desperate to keep his son from being sent to a losing battlefield and devises a plan. He decides to bring Takuto into the family as Riri's husband and send him to war as the second son. Feeling indebted to the Nanatsumori family, Takuto accepts, knowing there is no turning back. "I will let you spend just one day together as husband and wife." Granted only a single day, the two spend every moment until their parting, passionately loving each other.
