While Ichika Orimura departs to visit Kuramochi Engineering's laboratories, an unidentified enemy hacks into IS Academy's core and cripples its systems. To fend off the attack and repair the damage, his older sister Chifuyu enlists Ichika's harem: Houki Shinonono, Cecilia Alcott, Huang Lingyin, Laur...

Source: MyAnimeList