An assassination attempt is made on the life of the president by a teleporting mutant. This act upsets the entire world and entices the president to begin the mutant-human war as predicted by Charles Xavier earlier. In an effort to get to the bottom of the attack and prevent world-wide war, Xavier sends out Storm and Dr. Jean Grey to search for the teleporting mutant and discover the truth behind the assassination attempt.

Following a shocking attack on the President, the X-men must stand united with their deadliest enemies to combat a menace that threatens every mutant on the planet, and possibly all of mankind.