Bill Cage is stuck in a time loop, reliving the day he died in battle -- unless he can find a way to not only survive, but defeat the alien invaders.

Before Charles Xavier and Erik Lensherr took the names Professor X and Magneto, they were two young men discovering their powers for the first time. Before they were arch-enemies, they were closest of friends, working together with other mutants (some familiar, some new), to stop the greatest threat the world has ever known.