On the last day of summer vacation, Naoyuki goes to school for intending to swim after his forty-day long trip with Kunihiro investigating the Sunohara base. At the school pool, he meets Iriya who in equal surprise falls into the shallow pool, thinking that she is drowning. Saving her and treating her subsequent nose bleed, he begins to teach her how to swim. He discovers silver circular caps on her wrists that she says taste like electricity A military siren interrupts them, and Enomoto appears, telling Naoyuki to leave first. Passing through the military blockade, he receives a bug planted in his the upper-right part of his neck. The next day, he Iriya appears at school as a transfer student. After the opening ceremony, an air raid drill alarm sounds, causing Iriya to take Naoyuki and run into the secured shelter under the impression that a real air raid was about to occur. Inside, after losing a game, Iriya collapses. While trying to treat her, he is caught in an awkward position when Shiina and some other open the shelter.

Kunihiro orders Naoyuki to have a date with Iriya. On Saturday, Iriya waits for him for four hours before the meeting time of 10:00. They go to see the movie which begins at 10:30 where Iriya falls alseep, followed by both Kunihiro with Yūko and Enomoto with his assistant. Noticing that they have tapped his listening device placed in Naoyuki's wallet, Kunihiro manages to catch a picture of Enomoto and his assistant as they flee after being discovered. The commotion causes Iriya to take Naoyuki and run. Disposing of the Kunihiro's bug, they continue to be chased by Kunihiro and Yūko, under the impression they are enemies. However once they manage to ditch the two, they stop by a park where Iriya recounts a tale of herself and four others at the Nevada base when the group decided investigated the crash site of one of one of the group. The next day, Naoyuki finds her application for the newspaper club in his footlocker.

Enomoto takes Iriya back and treats her illness. Over a dinner of green ramen, Enomoto tells Naoyuki about the situation surrounding the secret war and Iriya's involvement in that war, announcing that the final battle takes place in three days, on October 26.