Detective Chung-su takes a secret mission from a dying president of a big company. The businessman wants to see his first love before he dies. The only information the detective has is that her name is Kkotnim and she now lives on an island called Tongbaek, off one of the country's southern ports. He rides on a private boat to the island with an anonymous passenger, dreaming of the big bucks he will get when he completes his mission. But the boat is wrecked in a fierce storm, and Chung-su and the passenger find themselves lying on the shore of a strange island. In the struggle to escape from the island, Chung-su meets up with five grandmothers who will not let him or the other men escape. During his captivity, he investigates if one of the grandmothers is indeed the love interest. Will he find out and escape from the island alive?