After her husband dies suddenly, Minhee (Yoo Da-in) goes to Jeju Island to live in her husband′s hometown. It is the place where she can meet people with whom she can share the memory of her husband and the house he cherished. As a writer and lifeguard, she begins to feel comfortable there until she learns about the past of Mokha (Cho Eunji), her neighbor. She thinks they can be good friends at first. But in fact there is some secret story in their relationship. The film begins with calm sorrow, but as the story develops, it reveals episodes that are impossible to expect. With the actors′ veteran performance that unfold this sad, unexpected, and cheerful story, The Cave becomes filled with both sadness and shining moments