Professor Xavier is Onslaught? Questions will be answered about the X-Men’s most insidious villain in this tell-all issue. Is Xavier truly the traitor his team of mutants believes him to be? And who is really behind the devastation of Onslaught?
Picks up where X-Men #54 left off: Xavier reveals himself to be the traitor, his mind corrupted by Magneto's psyche he wiped in X-Men #25 at the end of Fatal Attractions, as revealed in Uncanny X-Men #308.
— Description from Comic Vine community (comicvine.gamespot.com).
