Houtarou, to the Classic Literature Club’s surprise and concern, becomes interested in his past teacher’s changed feeling towards helicopters and his apparent survival of three lightning strikes. Eru is curious about Houtarou’s interest and tags along with him to do some research at the city library. Houtarou remembers his sister telling him that the weather across the mountains is quite different from that of the city, meaning that the lightning story is plausible, though unlikely. He then confirms through newspaper articles that his teacher often climbed the mountains and was present during a storm-involved incident, in which the rescue helicopters were unable to come for him. He concludes that his teacher was concerned about the weather over the mountains, and whether the helicopter could make its way through. Houtarou then says that people must be considerate around people like him. Eru is stunned by what Houtarou had said, but is unable to put her feelings into words. The mystery solved, Eru returns home. Houtarou thinks about how Eru inconvenienced herself to help him out of her free will, and says to himself that he owes her for that.