Soo-hyun (JI Yoon-ho) is a high school senior who has been raised almost solely by his mother Mi-Kyung (BAE Jong-ok). When Soo-hyun brings his close friend Yong-joon (LEE Won-geun) home to visit, Mi-kyung hits it off with the boy, and eventually even allows him to stay while Soo-hyun goes off to complete his mandatory military service. When Soo-hyun returns home several years later after finishing his time in the military, he goes on a road trip with Yong-joon and is left comatose after sustaining injuries in a car accident. Distraught, Mi-kyung places the blame for her son’s condition on Yong-joon, leading her to discover an uncomfortable secret the two have been keeping.