Hulk shrinks until he reaches the subatomic world of Terragonia where he meets Shamu-Shan, an old wizard. He believes the Hulk was sent by the gods as a champion against Kronak the Barbarian. A despot who overruled king Modrian, and using the Ruby of Shadows, enslaved them. Hulk believes such is not his problem, but when someone mentions Kronak is the strongest one there is, Hulk's pride is hurt and leaps toward the tyrant's castle to confront him.
After defeating Kronak's guards, Dragonus, a wizard, throws a potion which causes a stone wall to bury the Hulk, turning into Bruce Banner.
Presented before Kronak, the ruler decides to confront Banner on a sword fight to prove his people Banner is no champion. During the battle, Bruce turns into the Hulk. Scared to death, Kronak spawns from his mystic powered ring the Guardian of the Ruby, a powerful monster who can face the Hulk. But, Jade Jaws' strength increases, defeating his formidable attacker, shattering the ring.
Guards go to the aid of Kronak but Hulk dismisses them easily. Meanwhile, the peasants attack the castle.
In a desperate act, Kronak tries to defeat the Hulk to no avail. When Hulk is to land the final blow, he hears the crowd asking for Kronak, so he throws the tyrant to them. Kronak's scream is silenced under the crowd's attack.
Finally, as Shamu-Shan approaches the Hulk, he starts shrinking again until he vanishes from sight.