After losing her parents a few years earlier, a marquis’s daughter lives only to save her younger brother, who suffers from a serious illness. But when she discovers that her fiancé plans to kill her brother to seize the family inheritance, she is murdered as well to keep the truth buried. Given a second chance after returning to the past, she vows to protect both her brother and her house this time. To do that, she turns to a duke feared for his cold and ruthless nature and proposes a contract marriage based on mutual benefit. What begins as a practical arrangement, however, slowly starts to change as his icy attitude toward her begins to soften.