Independent bookstore owner Serena Hunt is forced to move out of her sister's home due to long-term exclusion by her brother-in-law Hank. To end her life of relying on others, she accepts an introduction from her benefactor Margaret York and registers her marriage with Zach, whom she meets formally for the first time.
The two feel a strong mutual attraction the moment they make eye contact at the city hall, but neither believes in love. Serena has witnessed her sister's imbalanced marriage and fears that passion will make women lose their independence; Zach, on the other hand, is convinced that all women approaching him are coveting the York family's wealth. He conceals his identity as a billionaire, disguises himself as an ordinary company employee, and makes an agreement with Serena to split expenses equally, live in separate rooms, and not interfere with each other.
The strange couple grows closer and closer under the same roof. Accidental sharing of the same bed, collisions in the bathroom, waist-supporting gestures, close dancing, and public kisses make their bodies cross the boundary before reason does. Zach also repeatedly uses his real power to secretly resolve the crises facing Serena's bookstore and family, but explains everything as "a friend's help".
Just as Serena truly falls in love with this "ordinary husband", Zach's true identity, premarital investigation, and secret acquisition of the bookstore are exposed at the same time. Serena finally realizes that the m
