Set in the era before Professor Charles Xavier and Erik Lehnsherr became mortal enemies as Professor X and Magneto, respectively, director Matthew Vaughn's X-Men: First Class follows the two former allies as they lead a powerful team of mutants on a mission to save the planet from nuclear annihilation. Charles (James McAvoy) and Erik (Michael Fassbender) were just young men when it began to appear as if the world was careening toward destruction.