"We Have to Fight the X-Men!"
Professor X's mind has been taken over by the evil Puppet Master as he orders his X-Men to take down the Fantastic Four. The X-Men arrive at the Baxter Building and neutralize the FF and they take Sue as a hostage.
The FF pursue the X-Men as they lead them to a strange plateau where they battle again, but not before the Puppet Master and the Thinker reveal themselves as the ones behind the fight.
With the help of the FF, the X-Men battle the Awesome Android and defeat the plans of the Thinker, who escapes with the Puppet Master. The X-Men return to their school and the FF head back home.