Seochodo, where the "Paradise Legend" has been passed down. It is a remote island in North Korean waters, forbidden to anyone by the North Korean marines who guard it. Then one day, an intruder is discovered on Seochodo. The intruder confesses that he snuck in to find the “outside world” mentioned in the "Paradise Legend." Surprisingly, the squad leader of the North Korean marines—who is supposed to protect the island—takes an interest in the intruder. As the two exchange conversations, they grow closer. However, the other marines, including the political officer, cannot understand at all what this “conversation” is supposed to mean.