Summary
After his sister, a devoted teacher, takes her own life due to her students’ cruelty, merciless loan shark Kim Sang-an is consumed by revenge. He assumes a new identity as a homeroom teacher at her school, intent on making the class of vicious pupils pay for what they’ve done. Confronted by truly monstrous students, he becomes a relentless collector pursuing a debt of suffering. This sparks a brutal, no-holds-barred conflict between a man with nothing left and the young demons who destroyed his world.