The X-Men have arrived too late to try and stop the Mutant Master and his Factor Three organization from preparing to trigger events that the terrorist organization hopes will start World War III, the first part of their world domination plan. Having arrived in Mutant Master's control room, they find the room empty with only a video screen of the Mutant Master mocking them of his impending victory. Acting on one of Beast's hunches, the X-Men flee the base inside one of Factor Three's flying saucers just before the base explodes. As they fly away from the explosion, the X-Men begin planning on how to prevent Mutant Master from triggering another World War.
Meanwhile, at another one of their headquarters hidden in the United States, Changeling begins to question Mutant Master's authority and planning when he brings up the fact that the Mutant Master left behind functional saucer ships at their old base. However, Mutant Master reasserts his authority over Changeling by showing his powerful weapons and reiterates his plot to take over the world. With Blob and Vanisher preparing for the first phase of their plan, the Mutant Master once more reasserts his domination over Changeling.

The X-Men have returned to Professor Xavier's School for Gifted Youngsters and have begun planning their attempt at foiling Factor Three's plot. Dividing the group into two and taking the remaining Factor Three saucers on their mission, Marvel Girl, Angel and Beast go to the USSR while Cyclops and Iceman head to stop the plot against the United States.
The three X-Men arrive in Russia in order to prevent a bomb that has been planted at a meeting of high ranking Russian officials. However, their arrival is spotted by Russian military soldiers who open fire upon Angel, Marvel Girl and Beast. Beast orders Angel and Marvel Girl to go on while he handles the soldiers and they enter the government building where the meeting is taking place. However, their path is barred inside by the Vanisher and Blob who are waiting there to stop the X-Men from interfering with their plot.
Back at Factor Three's headquarters, a revived Professor X tries to rationalize with the Changeling, telling the already doubting mutant that a nuclear war would make the planet harmful to both humans and mutants alike. Put further into doubt by these words, the Changeling is still loyal to the Mutant Master and strikes Xavier for daring to speak out against their plot. However, when the Changeling threatens to execute the Professor, the Mutant Master prevents him from doing so.
Elsewhere, Cyclops and Iceman visit the military base that Factor Three intends to gas and try to explain the situation to the commanding Colonel on site. However, the Colonel finds the story hard to believe, with no time to waste the two X-Men decide that there is no other choice but fight their way to the weapon and disarm it. This causes a clash with the military, which Cyclops and Iceman are able to keep at bay with their mutant powers.
Finally, back in Russia, the other X-Men are attacked by Blob and Vanisher who are armed with high tech weapons. While Blob is disarmed by Angel, who also takes out the Factor Three minions that accompanied them, when Vanisher attempts to use his gas gun on Angel, Marvel Girl uses her telekinetic powers to knock Vanisher out and redirect the knock-out gas into Blob's face knocking him out as well. However, the Russian soldiers catch up to Marvel Girl and the Angel and hold them at gun point accusing them of being assassins. Not listening to the X-Men's story, they find themselves locked in a cell with the Beast (who was also captured) and their foes.

---