Accel World: Infinite∞Burst EP1 アクセル・ワールド インフィニット・バースト

A mysterious black cloud kicks Haruyuki and his friends out of an online game. Unable to reenter, they discover this isn’t an isolated incident—the cloud is spreading. Haruyuki and the others soon learn that to protect the bond that connects them, they must confront an ancient being that's been sealed away since the dawn of the “Accelerated World”!