Separated from their comrades due to a monster's attack, Kaeko and Miyako find themselves in a small hut. Inside, they discover the diary of a Japanese soldier who washed ashore on this island during the war. The diary reveals a part of the island's secrets: "Mysterious Rituals," "The Boy Who Doesn't Grow," and "The Deformed Monster." What seemed to be solved turns out to lead to new mysteries, and the girls seek further clues for their escape amidst the confusion...