"The End of the World As We Know It, Part 2"
Continues from Uncanny X-Men (1981) #377.
Apocalypse has gathered "The Twelve" in his Egyptian base. While they are in place in the Celestial machinery, the remaining X-Men fight off the Skrulls and Children of the Sun.
Apocalypse's plans seem unstoppable, until Magneto is suddenly drained of his power. With the Celestial mechanism shut down, Apocalypse shifts his focus to taking over the body of Nate Grey while "The Twelve" try to stop the Living Monolith from overloading.
In the end, Cyclops sacrifices himself and becomes merged with Apocalypse, starting off the "Ages of Apocalypse" story arc.