Sunho falls off the school building. Sunho's parents are devastated to see their boy unconscious in the hospital. Meanwhile, Sunho's friends secretly delete a video playing the "Avengers Game" on their phones before meeting with the detective on Sunho's case.

Moojin and Inha finds out that Sunho was a victim of school violence and demands to the police for a reinvestigation of the accident. Meanwhile, Jinpyo tells Joonsuk to confess about the video to his teachers. What is the hidden truth behind all the lies?