Yuri, who has been married for five years, is far more energetic than her appearance suggests. Recently, she became passionate about running and even participates in marathons. One day, she accidentally trips and injures herself during a jog, and is unexpectedly rescued by her secret lover. For Yuri, who is usually treated like a housemaid by her husband, his gentlemanly and gentle demeanor deeply moves her, leading them to cross the line. Unable to suppress her growing feelings, their affair intensifies as they embark on a trip together, nurturing a new and forbidden relationship.