.hack//Quantum

.hack//Quantum is an OVA set in The World R:X, the latest version of the massively multiplayer online game at the heart of the .hack franchise. It follows a trio of friends who play together as a team: Tobias, Mary and Sakuya.

Eager for adventure, the three challenge The One Sin, an event with a reputation for being impregnable. Their attempt quickly goes wrong: they lose their way in the maze and unintentionally end up trapping other members of their guild. All the while, a mysterious cat is watching their blunder. Is it just another player character, or an NPC with a purpose of its own?

What starts as a comic misadventure gradually becomes something far more serious, as the girls stumble onto strange phenomena hidden within the game and begin to suspect that what happens in The World can have consequences for the people behind their characters. Like other .hack stories, Quantum blends lighthearted adventure among friends with a mystery about the true nature of the virtual world.