Light Novel Accel World Vol. 07: Armor of Catastrophe
In order to cleanse Silver Crow (aka Haruyuki), Kuroyukihime and the rest of Nega Nebulus launch an operation to rescue Ardor Maiden. In the midst of this dangerous mission, Silver Crow manages to make contact with Ardor Maiden, but in doing so, he invades the forbidden territory of the Imperial Palace. There he has a vision of Chrome Falcon and Saffron Blossom--but what do they have to do with Haruyuki?!