A program designed to show each girl her perfect fantasy with Ichika should be nightmare fuel for a harem protagonist, but instead it becomes the permission structure the show needed: every girl gets to want him without apology, without compromise, without another girl in the frame. The World Purge doesn't resolve the harem, it validates it. This is what the series was always building toward, the moment where the competition stops being a joke and becomes honest.

While Ichika is away at Kuramochi Engineering's research labs, an unknown attacker hacks IS Academy and shuts down all of its systems. His sister Chifuyu sends the five girls who own personal IS units, Houki, Cecilia, Lingyin, Laura and Charlotte, into the IS Core Network to restore control, while Tatenashi holds off an armed assault on the school. Inside the network, a hidden program called World Purge traps each girl in a fabricated reality built around her ideal romance with Ichika. Once Ichika returns, it falls to him to rescue the five and wake them. The single OVA episode mixes mecha action, comedy and ecchi.