Eons ago, in the Valley of Flame, the peaceful Small Folk were oppressed by their savage neighbors, the Killer Folk, until one day a champion arose to protect them: a crimson T. Rex known as Devil Dinosaur. The Killer Folk flee from its savage jaws and peace settles on the primeval valley. The scene is observed by two members of the starfaring race known as the Celestials; One, Devron, is impressed that the Small folk have compensated for their disadvantages by this alliance with a more powerful denizen of the valley. The other, Gamiel, disapproves of this deviation from the expected pattern of development, so, as the Killer Folk pray for a deliverer, the reactionary alien provides one for them: the Hulk, plucked out of his timestream and plunked down in the valley.
The Killer Folk, insisting that they wish only to be left alone, strike a responsive chord in the Hulk’s breast, and he agrees to become their champion. Hulk leads the savages to reclaim the valley and the battle between the behemoths green and red is on. Hulk clobbers Devil Dinosaur into unconsciousness but when Moon-Boy vows to give his life to protect his thunder lizard friend, Hulk relents, choosing to leave his foe alone, and preventing the Killer Folk from slaying it as well. Devron, observing Gamiel’s interference with the natural development of this world, is forced to intervene as well to correct the deviation. He does this by mutating the T. Rex into a massive monster, which attacks Jade Jaws. Realizing the release of energy will call attention to their misdeeds, the two Celestials teleport the monstrous antagonists up to their ship and cage them. Unfortunately for them, Hulk and Devil Dinosaur break out of the cage and lay waste to the ship, stopping only when Hulk breaches the bulkhead, sending the four into the airless reaches of outer space. The Celestials’ superiors intervene, sending Devil Dinosaur and Hulk back where they belong, and propose a less demanding assignment for the unseasoned pair: observing the first meeting of the Skrulls and the Kree. “After all, how much trouble could they possibly get into there?”