Tode, leader of the Deviants, has decided that that big Celestial mothership out in orbit has to go, and sends up a giant bomb ship on a suicide mission. Meanwhile, NASA is also curious and sends up a shuttle to take photos of the ship. Meanwhile, the rest of the Eternals are busy in the Uni-Mind ritual, so Sprite is left to detect the danger and decides to enlist the help of the Forgotten One, a nameless Eternal exiled by Zuras for his pride and meddling in human affairs (and implied to be the source of various hero myths, I think he was made to be explicitly the source of the Gilgamesh story in later non-Kirby stories).
Sprite creates a space-suit and ship for the Forgotten One and then the representatives of the three races of Earth converge on the ship of the One Above All, who acts quickly and efficiently by switching the crews of the three ships, letting them each fulfill their missions after a fashion.
I think these side-stories in this series are often better than the main action with Ikaris and the others. Kirby clearly had a vast mythology that he only started to explore, and this issue has a nice sense of wonder and discovery.
Mike Royer inks the cover and 17-page story.