On the way back to New York, the Avengers refuel their helicopter in Chicago where Captain America demonstrates the devices Tony Stark recently installed in his shield. Captain America is depressed over Bucky's death and the Avengers console him with fan mail. Rick Jones offers to take Bucky's place, but Captain America declines and declares that he will devote his life to finding Bucky's killer.
Meanwhile an aircraft lands in a remote South American jungle enclave and the pilot delivers supplies and a newspaper to the robed and hooded figure know as Baron Zemo. When Zemo reads that Captain America is still alive, he becomes enraged and tells the pilot how, years ago, his hood was glued permanently to his face by Captain America. He has since searched endlessly for a solvent for the super strong Adhesive X, but he has found none. He shouts that he has been robbed of his revenge against Captain America as well. He then orders his pilot to locate three people to help him obtain revenge.
In New York, the Teen Brigade watches fearfully as the Black Knight, on his winged horse, sprays the city with a powerful adhesive, paralyzing traffic. Melter and Radioactive Man then wreak more havoc. The Avengers, just returned from their mission , attack the three evildoers but are forced to retreat when Giant Man and Captain America become glued to the street. Iron Man cuts out the section of pavement they are stuck to and tows it with a truck to Avengers headquarters. When Zemo arrives on the scene in his Heli-Hovercraft, his three allies apologize for letting the Avengers escape and advise him to strike before the Avengers discover a solvent for the glue. Secretly pleased with the prospect of finally getting rid of his hood, Zemo tells his allies their next move.
After several fruitless attempts by the Avengers to free Captain America and Giant Man, the Wasp telephones the penitentiary where Paste-Pot Pete, the world's greatest authority on adhesives, is incarcerated. In exchange for a shortened prison term he reveals where his Super-Dissolver is stored, and Iron Man transports it to the Avengers Mansion. Minutes later, Captain America and Giant Man are free and Captain America outlines his plan to defeat the Masters of Evil.
At the evildoers hideout, Zemo orders his pilot to refill their Adhesive X containers but Rick Jones and the Teen Bridage sneak inside, tie up the pilot, and fill the canister with Super – Dissolver instead. The Black Knight is the first to notice something wrong when he spray frees the people who were stuck before but can act, Thor attacks. Elsewhere, the Radioactive Man also discovers the defective adhesive as Giant Man and Iron Man challenge him. Iron Man wraps the criminal in lead foil with a special device and sends him aloft on a balloon, helpless. Then the Melter appears, whom Iron Man defeats with a high pressure stream of water that wrecks his melting beam.
Zemo soon discovers Rick and the Teen Brigade and hypnotizes them, but before he can learn what they have done, Captain America attacks. Just as Captain America overpowers Zemo, the pilot stuns him with a bullet. Zemo flees in his aircraft as Giant Man captures the pilot. Thor arrives carrying the Black Knight on the evil doer's horse, and the criminals are turned over to the police. As Iron Man brings the teenagers out of their trance with his palm signaler, Zemo's aircraft suddenly falls from the sky. Captain America explains that Zemo must have opened the canister of tear gas that the Teen Brigade substituted for the container of Super Dissolver.