Avengers : Season 1, Episode 13: "Gamma World Part Two"

"Gammaworld Part Two" - The Leader’s master plan has been unleashed, and half of North America has been turned into Gamma Monsters, including the Avengers! In 24 hours, the entire world will be under the Leader’s control. Our only hope? Hawkeye. His only hope? Finding the Incredible Hulk and convincing him to stop the Leader from turning Earth into Gamma World.