After losing both her parents, Failan emmigrates to Korea to seek her only remaining relatives. Once she reaches Korea, she finds out that her relatives have moved to Canada well over a year ago. Desperate to stay and make a living in Korea, Failan is forced to have an arranged marriage through a match-making agency.

On 31 January 1968, 31 North Korean commandos infiltrated South Korea in a failed mission to assassinate President Park Chung-hee. In revenge, the South Korean military assembled a team of 31 criminals on the island of Silmido to kill Kim Il-sung for a suicide mission to redeem their honor, but was cancelled, leaving them frustrated. It is loosely based on a military uprising in the 1970s.

A member of Coast Guard Platoon 23, Private Kang monitors a high-infiltration stretch of beach lined with barbed-wire fencing. Driven by the belief that killing a spy is the highest honor, he waits for a chance to prove his worth.

Yu-jeong is suicidal, yet she reluctantly goes to prison for volunteer work. There, she meets a prisoner who is waiting for death penalty. The two quickly fall in love despite their differences, yet they do not have much time.