Infinite Stratos - S01

While Ichika Orimura leaves to visit Kuramochi Engineering's laboratories, an unknown enemy hacks into IS Academy's core and cripples its systems. To fight off the attack and repair the damage, his older sister Chifuyu calls on Ichika's harem: Houki Shinonono, Cecilia Alcott, Huang Lingyin, Laura Bodewig, and Charlotte Dunois. Together, they use virtual reality to take on their opponents inside IS Academy's network. Without the girls knowing, a piece of malware called "World Purge" activates once they enter the digital realm. The program traps them in fabricated realities, where each of them lives out an ideal romantic version of her bond with Ichika. When Ichika returns to IS Academy, it falls to him to rescue the five girls and wake them from this virtual reality.