To protect her frail younger sister Hiroko from a demanding marriage, Asako offers herself as a substitute bride to Kido Shintaro, a formidable and merciless military officer who seeks a wife solely to bear children. Though the arrangement is loveless and Kido is imposing, Asako accepts her fate for the sake of her sister's happiness, unaware of the turmoil that awaits her on the day of the ceremony.