上流階級である七ツ森家の令嬢・りりと七ツ森家に幼い頃から仕える下男・拓人。子供の頃から知っているりりと拓人は心の中で想いあっているが、身分の違いもありその気持ちをお互い胸に秘めていた。そんなある日、七ツ森家の長男・篤史に従軍命令が届く。将校でもある父の徳治は長男を劣勢にの戦地にみすみすいかせたくなくて一計を案じる。拓人をりりの婿として七ツ森家に迎え、次男として出兵させることにしたのだ。七ツ森家への恩義を感じて、もう戻れないとわかっていて引き受ける拓人。「1日だけ夫婦として二人で過ごさせてやる」たった1日だけ二人で過ごせることになった2人は、別れの時間までひたすら愛し合うのだった。

Riri is the daughter of the Nanatsumori family, a family of high social standing, and Takuto is a servant who has served the Nanatsumori family since hood. Riri and Takuto have known each other since they were ******** and secretly harbor feelings for each other, but due to their difference in social status, they keep their feelings hidden. One day, Atsushi, the eldest son of the Nanatsumori family, receives orders to join the army. His father, Tokuji, who is also an officer, does not want his eldest son to go to the battlefield where his army is losing, so he devises a plan. He decides to take Takuto into the Nanatsumori family as Riri's husband and send him off as the second son. Feeling indebted to the Nanatsumori family, Takuto accepts, knowing that he will never be able to return. "I will let you spend just one day together as husband and wife." The two are given just one day to spend together, and they make love to each other until it is time to part.