A deaf man and his girlfriend resort to desperate measures in order to fund a kidney transplant for his sister. Things go horribly wrong, and the situation spirals rapidly into a cycle of violence and revenge.
Young married couple Yoon-hee and Jung-hyun go on a road trip, and along the way they pick up a lone drifter, M. M turns out to be a violent and sadistic psychopath who terrorises the couple at every turn. After capturing Jung-hyun, Em gives him a choice: submit to torture or allow Em to kill Yoon-hee.