Akira Hayami's younger brother Kazu falls into a coma while playing The World, the online game at the center of the .hack series, and she logs in herself as BlackRose to find out why. A beginner at first, she soon meets Kite, a Twin Blade whose friend Orca was struck down the same way, and the two set out after the secrets hidden inside the game. This light novel retells the four original .hack games from BlackRose's side, adding the parts of her life that happen offline.