Uncanny X-Men (2016-2017) #7

"APOCALYPSE WARS" CONTINUES! Fearing their teammate Archangel has once more fallen under the sway of the villainous Apocalypse, Psylocke and Magneto have embarked on a mission to save his life. But they're about to make a discovery that will make them doubt everything they thought they knew! Meanwhile, Sabretooth and M make a horrifying discovery of their own in the Morlock Tunnels beneath New York City…