Major crimes unit detective Seong-jin arrests Tae-sung for petty crimes, but shocked to find out that he is the notorious serial killer. However, Seong-jin becomes doubtful of his identity as the serial murder case is investigated.

Park Young Ho is a new transfer student in school. He quickly becomes the target of top bullies of school because he stands up against them to protect a student from getting bullied.

Yeong-ho completely dominates Gi-tae and his gangmates. After hearing what happened, an 11th-grader offers him the spot, but Yeong-ho refuses. Meanwhile, Dae-chun who was suspended for school bullying is back and he’s been keeping a low profile.

Jin-seok, 21-year-old, moves into a new house with his family. He suffers from a slight schizophrenia but he carries an ordinary life under the warm care of the family. His older brother Yu-seok is a decent college student, a mentor, and role model for Jin-seok. One night, his beloved brother is kidnapped by unidentified assailants before Jin-seok's eye. Jin-seok can’t recognize their faces, but can remember only the VIN that matches with no car. After long silence of 19 days, suddenly Yu-seok returns home, but remembers nothing which had happened in the meantime. And soon Jin-seok feels Yu-seok is a total stranger.

After completing his required decade of military service and being honored as a hero, a North Korean sergeant makes a sudden shocking attempt to defect to the South, risking life and limb for the chance to finally determine his own destiny.