The Uncanny X-Men #294 : Overture (X-Cutioner's Song - Marvel Comics)

X-Cutioner's Song: Part 1 of 12. "Overture!" Guest-starring X-Factor and X-Force. The X-Men's world is turned upside down one fateful day when an assassin's bullet finds its mark. Professor Charles Xavier, champion of a co-existence between humans and mutants, has just been shot. And the gunman is none other than Cabal, leader of the mutant outlaws known as X-Force. Story continues in X-Factor (Vol. 1 ) #84.