Based on a true story, Silmido tells of the 1968 secret plot by South Korea to assassinate the North Korean leader Kim Il-Sung. A rag tag bunch of misfits and death row criminals are transported to Silmi Island as part of a secret plan to assassinate North Korea's leader. After months of grueling training including physical and mental abuse and even death, the would-be assassins are ready to undertake their perilous mission. However, as politics change, so too does the mission of the Silmido team.