Persisting Kanzashi to be his partner, Ichika looks up on maintenance assistance for Kanzashi's personal IS, but it's not that simple. Meanwhile, upon realized Ichika insisting to pair with Kanzashi for the tag tournament, the girls take their time training more aggressively. As Tatenashi has Houki to team up with her, she analyzes Houki's physical body, to her surprise to learn that her aptitude is up to level S already. When Kanzashi takes her IS, Uchigane Nishiki, for a test run, it malfunction, then Ichika saves her before she crashes. Having a change of heart towards Ichika, she indirectly agrees to be his partner. Then Ichika shares data from Byakushiki to help improve Kanzashi's IS, and haves other students to gladly help. Returning to his dorm room, Tatenashi insist Ichika for another massage, talking how important younger siblings can be for their elders, knowing how strict they can be for their protection. Kanzashi having to give Ichika sweets as gift, she reaches his door only to overhear that Ichika’s generous offer was Tatenashi's idea, leaving her heartbroken.
簪とタッグマッチトーナメントのペアを組むべく、近付く一夏。しかし、簪は頑なに心を開かない。そんな中、ひとり、打鉄弐式の飛行テストを試みる簪だったが、突然、空中で機体脚部から火花があがり――！？
一方で、楯無は箒をトーナメントのペアに誘う。交錯する姉妹の想い、その行方は……！？
이치카가 졸졸 따라다니지만 칸자시는 좀처럼 마음을 열지 않는다.
그리고 혼자 개발해온 전용기 가동실험에 나서는데...
처음에는 순조롭게 작동하던 우치가네 2식이 갑자기 자세제어에서 에러를 일으키면서 추락한다.
