The chapter opens with a flashback to the beginning of the previous chapter, in which Hiroshi, the teacher, and Hiroshi's friend, Natsumi, are swimming in the shallow waters of the ocean. Hiroshi has just returned from a trip to a nearby town, where he has been asked to chaperone a group of students, and he is eager to get back to his normal duties as a teacher. He is worried about the safety of his students, but he is also concerned about his own safety, as he has no idea what to do if he is caught in the act of running away from the group.