Gangjae (Park Hyuk-kwon) is leading an outwardly happy, inwardly tortuous life. Married, with a high school-aged daughter and a good job, he has achieved everything that society expects of an average middle-class man. But emotionally he is in the process of unraveling, and his well-ordered outer life is starting to show cracks as well. The plot of A Break Alone is divided between two time periods, and the film shifts restlessly back and forth between them. Ten years in the past, Gangjae meets an attractive young yoga teacher named Siyeon (Yoon Joo) and falls in love with her. They start an affair, which he manages to keep secret. But eventually she starts feeling frustrated and disillusioned with adultery (and love), and decides to marry someone else.