At their regular monthly meeting, the four remaining Avengers decide to search for the Hulk to try and bring him back to the team. Using an Image Projector, Iron Man communicates with the Fantastic Four, Spider Man, and the X-Men, hoping for a lead on the Hulk's whereabouts; but the heroes are too busy with their own affairs to help. Thor suggests the Avengers radio Rick Jones, and when he receives their message, he hikes into the desert to find the green-skinned giant. A frightened rancher warns Rick about a monster he has just encountered and Rick soon discovers the Hulk fishing for the rancher's car from a nearby lake. Rick warns the Hulk that the ranhcer has gone for the police and the Hulk carries Rick to Bruce Banner's hidden laboratory. There his Gamma Ray Machine changes the Hulk into the exhausted Banner, and Rick helps him to bed.
Unfortunately the radiation dosage is too weak, and a short time later Banner unexpectedly changes back. Completely out of control the Hulk shatters the heavy chamber door and escapes. Rick locates a Teen Brigade radio transmitter, and the teenagers summon Iron Man, who in turns notifies Giant Man, the Wasp, and Thor. Iron Man arrives first, but before he can land, The Hulk starts punching him. Giant Man and the Wasp, reduced to insect size, arrive next, only to be caught in a barrage of needles stripped from a cactus and fired at Iron Man by Hulk. After they take cover in an anthill, Giant Man commands the ants to dam an underground stream, forcing the water to spurt into the Hulk's face. Despite this interruption, the Hulk's battle with Iron Man continues.
When Thor arrives, he sees Iron Man whirling the Hulk in the air with his magnetic repulsers. Thor commands the Hulk to return with the Avengers, but the green skinned giant escapes through a mine shaft and clambers aboard a train. Iron Man and Thor give chase, but the Hulk heaves the caboose at them and tangles Thor in a steel cable. Then Giant Man appears, but the Hulk stuffs sacks of flour from a freight car into the engine's smokestack, and Giant Man, blinded by the powder, is slammed into a tunnel roof as the train carries the Hulk away. By concealing himself in a dump truck, The Hulk evades a police dragnet, and days later is picked up by a freighter in the Atlantic Ocean. Watching on a view screen is the SubMariner, and when the Hulk recovers and swims to nearby island, Namor is there waiting. At first they fight, but Namor, more powerful than the Hulk underwater, subdues him with a whirlpool. Soon, bound by a shared hatred of humans they agree to an uneasy alliance against the Avengers.
Sometime later , the challenge from the Sub Mariner and the Hulk arrives and the Avengers take a jet bathyscaphe to Gibraltar where their antagonists await them in a cave used by the British in World War II. An arduous battle ensues, in which both sides employ abandoned British war material as well as their own superhuman abilities. Suddenly Hulk changes back to Bruce Banner and has to run away to avoid revealing his secret identity, and the Sub Mariner , weakened by lack of water, is cornered. Although feeling betrayed by the Hulk, Namor refuses to surrender. Then a trickle of water from the cavern wall restores enough of his strength to allow him to break free and escape.