Professor Charles Xavier runs a very unusual school. Xavier and his students are mutants, individuals born with an "X-tra" power compared to regular people. He puts his first students, Cyclops, Angel, Beast and Iceman, through a series of training exercises before welcoming their newest addition, Marvel Girl. Just as they are getting to know each other, and emergency erupts. Someone is hijacking all of the U.S. military's metal arsenal, including I.C.B.M. missiles and tanks. After making his ransom demands, Magneto shows himself in order to take over an entire base. The X-Men arrive to fight him, and manage to drive him off, ending his scheme.
