Satoko is a noblewoman from a wealthy family. As she comes of age, she is expected to find a husband. However, she has a serious heart condition that makes it difficult to find a suitable match. Because of this, she tells every potential suitor about her illness so she does not deceive them, but many proposals are rejected because of it.
One day, while out in town, she is kidnapped by men who intend to kill her. Then Shinpei Gotou appears. In order to save her life, she proposes marriage to him.