"The Peril and the Power!"
This is it, the final battle with Doom but two of the Fantastic Four have plans of their own, as Johnny and Ben take on Doom one at a time. Doom is still too powerful for them - augmented by the stolen cosmic energy of the Silver Surfer, even though Ben nearly brings Doom down.
Reed and Sue buy some time until Reed's plan finally goes into effect. Doom is sapped of power by one of Reed's inventions, but it's not enough to stop Doom, but enough to make Doom follow the flying weapon into space, the one place the Silver Surfer has been forbidden to fly to.
Doom looses his power as the punishment left by Galactus to keep the Silver Surfer on Earth.