From the diary of a Japanese soldier who had drifted to the island in the past, a part of the island's secret has been revealed. The master of the island was once a silent boy whom Sakuya and the others had encountered. Not only does he not grow, but to escape from the island, they must outsmart a boy who cannot die even when cut! To do so, they have no choice but to destroy the very system of the island itself!? The plan devised by Torino was, in a sense, a ruthless one. While fighting against a horde of monsters attacking the girls, Sakuya ends up getting separated. However, she coincidentally meets Hina, who is Torino's beloved. Additionally, Sakuya reunites with Shoko, who is with a mysterious old woman and a young man who does not grow. What history of the island and what secrets of the young man will be revealed there…!?