時は大正。
遠野麻子は強気な性格が災いし、行き遅れた子爵令嬢。
親からも冷遇され、妹のひろ子さえ幸せなら…と願う日々だった。
しかし、最愛の妹に冷酷と噂の陸軍大尉・木戸慎太郎との縁談が来てしまう。
麻子は身代わりに嫁ぐことを慎太郎に提案するが――「妹の代わりに俺の子を産んでもらおうか」と迫られて…
Despite being the daughter of a viscount, Asako is rejected by high society and treated as a nuisance by her parents. When a marriage proposal suddenly arrives for Asako's younger sister from none other than Captain Kido, a soldier known for his coldness, she doesn't hesitate for a moment. To protect her precious younger sister, Asako volunteers as... a substitute bride!
