An unexpected cohabitation begins between two completely different people. Yeo-won, a marketing team employee who is most comfortable alone, and Jung-jin, a sales team manager who always tries his best to keep smiling. They don't understand each other at all. One day, Jung-jin, who is left on the streets after a sudden breakup, unexpectedly asks Yeo-won, whom she coincidentally meets, to let her stay over, and an unforeseen cohabitation begins. Yeo-won is uncomfortable with her space being invaded, but as time passes, she begins to recognize the loneliness and wounds hidden behind Jung-jin's warm smile. Conversely, Jung-jin comes to understand the human side hidden behind Yeo-won's cold exterior and the true rest she sought in her alone time.