Shin, a serial killer, has had a profound impact on South Korea. Jihu Seo, whose father fell victim to Shin's crimes, meets Duseok Kim, a former detective who also suffered at Shin's hands. Duseok trains Jihu to become a weapon for revenge against Shin, even if it means killing him with his bare hands in prison. "Since 1997, Korea has not implemented the death penalty. If no one else is upholding justice, what other choice do we have?"