Kawaki and Himawari's class goes on a field trip to an uninhabited island. The field trip suddenly starts to feel unsettling, but the students try to work together to overcome bizarre incidents.

Kae has been taken away and Kawaki and Himawari must face a dangerous assassin. They try to corner the enemy, but their opponent proves to be powerful. Will Kawaki be able to save his friends and accomplish his mission?