Meekyung lives apart from her husband and raises Soohyun, her high school-aged son. One day, Soohyun brings home his friend Yongjoon to stay. A few years later, after completing his military service, Soohyun gets into an accident while on a trip with Yongjoon and is hospitalized in critical condition. Soon after, Meekyung discovers a secret her son and Yongjoon have been keeping from her.