Rei goes to an anime convention and ends up in a world created by the desires of anime fans. Rei doesn't know how to get back and the world starts to collapse because the convention is coming to a close.

This OVA is a summary of the first three episodes of Hellsing, with the animation style of Hellsing Ultimate and following the events of the Hellsing manga.

In the year 2062, Earth finds itself fiercely battling Artemis—an AI which rebelled against humankind following a grand-scale workforce automation project failure years prior. In the hope of winning the war, a group of three highly skilled human warriors is assembled, known as the guardians of humanity. Empress, the last surviving guardian, wakes up alone in an empty research facility. Unable to recall anything from the past except a place called "Lighthouse No. 8," she begins to search for answers. It is not long before she discovers an impending threat from Artemis—and she is the sole person who can save the world from destruction.

What do an alien, former ninja, weak telepath, and boy pretending to be a girl have in common? They are all classmates at Kashihara Girls' Academy, and they hide their true identities from the world. Rikka, Chiyo, Sekine, and Tsubasa seem like the best of friends, but they each harbor a monumental secret that they cannot reveal, no matter what. In order to continue masquerading as normal middle school girls, each of them must invent creative ways to conceal their true selves. But that is easier said than done, as the four students end up entangled in numerous shenanigans along the way.