Joon-Ho Bong directs this Korean murder mystery. In a remote village in South Korea, a lonely single mother looks after her mentally handicapped son Do-jun (Weon Bin) while scraping a living as an acupuncturist. But her simple, poverty-stricken life is suddenly plunged into chaos when her son is arrested for the brutal murder of a local schoolgirl. Convinced that he has been set up, the mother sets out to prove her son's innocence to the police, who seem more interested in closing the case than in researching other possible leads.