A group of soldiers is hauling toxic waste out of Chicago, and stop when they hear noise come from inside their trailer. Stopping to check it out, they find that to the unfortunate luck, the Hulk had chose their vehicle to take a nap in. Furious at being woken up, the Hulk lashes out. When the soldiers attack him with their machine guns, the Hulk easily swats them away. He smashes their truck getting toxic waste spilled all over him and then flees off into the wilderness completely unaware that he is being spied by a UFO flying in the sky. Aboard the ship, the Hulk is being watched by an alien piloting the craft who hopes to take control of the Hulk and use him to conquer the Earth.
While at Hulkbuster Base, as preparations are being made for the presidential visit, lab worker Harold Conrad works overtime to get the results of a cellular scan that was collected from Glenn Talbot for Colonel Armbruster, who is suspicious of the recently returned Talbot. Going over the results, he finds a startling revelation in them and rushes off to tell Armbruster. However, before he can get out of the lab, a mysterious gun man opens fire on him. This mystery killer then drags off Harold's body to a storage room and burns the computer print out on Talbot.
While out in the open, the Hulk laments once more over his lack of friends, wishing for nothing more to stop being hounded and have a friend. As Hulk expresses how he is alone with nobody for company except for his shadow, the Hulk is shocked when his shadow comes to life and attacks him. The shadow creature easily gets the best of the Hulk and explains who it is: He calls himself Warlord Kraa, and explains how many years ago he and his people came to Earth and attempted to invade it by taking over peoples shadows. This invasion was easily defeated and captured, except for Kraa who managed to escape to plot revenge. He explains that the combination of the Hulk's gamma spawned nature and his recent dousing with toxic chemicals allowed for Kraa to take control of the Hulk's shadow which he plans to use to take over the world. The Hulk tries to take a swing at him, but finds that fighting your own shadow is a very hard thing to do.
While back out in New Mexico, General Ross goes out horseback riding with Betty and Glenn. They spend the day rafting and other outdoor activities. The momentary relaxation allows General Ross to think about things and be thankful that they can take their minds off of things, especially the Hulk.
The Hulk meanwhile is fighting his Kraa possessed shadow, the battle taking them to a nearby oil field. However, despite Kraa's tactical advantage of being a literal shadow, the Hulk is not easy to defeat. Just as he is gaining the upper hand, Kraa notices that the sun is rising, sapping his power. Then, flood spotlights turn on, triggered by their battle creating more light. All the light sources create so much light that no shadow can exit and Kraa is seemingly destroyed.
With the battle over the Hulk picks himself up an walks away from the scene, eventually passing out and reverting back into Bruce Banner. As reports of Hulk's travels from Canada to his most recent sighting in Oklahoma reach Hulkbuster Base, Banner wakes up and heads right there. He enters the office of Colonel Armbruster just as he finishes briefing Betty, Glenn and General Ross on the Hulk's recent activities. Surprised by the sudden appearance of Bruce Banner, Armbruster pulls out a gun and shoots Banner. As Banner collapses to the floor, General Ross asks Armbruster what he's done, Armbruster tells Ross that he's done what is good for his nation.