[By the Studio that brought you Kim Sang-an is a cold-blooded loan shark.When his younger sister, a schoolteacher, takes her own life after relentless bullying from her students, he becomes the homeroom teacher of those very students to collect the price of her life.A merciless loan shark who will collect his debts even if it means descending into hell and a class of devil-like students...A vicious, twisted teacher-student relationship.