Keita and Yuri who visited the countryside by relying on Hatsue, a big aunt of Yoko who is a classmate, for the task of Japanese history. The purpose was to listen to the war experience and put it together in a report, but Keita had another reason. She was asked by Mayuko of the development department to experiment with a "remote communication blocking system". When the experiment started, Seven received a strange radio wave ...
日本史の課題のために、クラスメイトである陽子の大叔母、初枝を頼って田舎を訪れたケイタと優璃。表向きは戦争体験を聞いてレポートにまとめるのが目的だが、ケイタには別の理由があった。開発部の真由子から“遠隔通信遮断システム”の実験を頼まれていたのだ。実験を開始するとセブンが奇妙な電波を受信して…。