Gamma World

"Gamma World" is the 12th and 13th episode of The Avengers: Earth's Mightiest Heroes.

Part 1
The Avengers' pursuit of Hawkeye is interrupted by S.H.I.E.L.D asking their help to check the mysterious Gamma dome around the Cube. Those who went early were taken out by Abomination and mutated into varied Gamma monstrosities. The Avengers and Doc Samson must investigate the Gamma dome before it expands to populated areas.

Meanwhile, Hawkeye sneaks into a HYDRA warehouse and captures Black Widow. As he cannot turn her to SHIELD since they wouldn't believe him, he decides to find the Avengers.

The Avengers and Samson wear safety suits to go inside, and face Zzzax and the U-Foes, who use Gamma devices to enhance their own powers. During the battle, Wasp's suit is torn and the Gamma radiation turns her into a wasp monster, and the same happens to the S.H.I.E.L.D. agents acting as backup, who turn into different creatures and attack the Avengers by Leader's orders.

Thor and Samson reach the dome generator, but it's guarded by the Wrecking Crew, who also use enhancing devices. While Thor and Samson fight the Wrecking Crew, Black Panther sneaks and destroys the Gamma generator. This reverses the mutations on Wasp and the agents (and the similar mutation that almos undergoes T'Challa himself).

While it seems the day is saved, the Leader, Abomination and Absorbing Man are nowhere to be found. They actually are outside Las Vegas, where the Leader declares his little test a success and activates a new dome in Las Vegas.

Part 2
The Gamma dome from Las Vegas affects all the Avengers save for Thor, due to his Asgardian physiology, and Doc Samson, who is already Gamma-altered. Hawkeye, who was bringing Black Widow, barely averts the dome and decides he needs the help of Bruce Banner.

Hawkeye finds Hulk running away of the Hulkbusters, but Hulk doesn't want to go with Hawkeye. Hawkeye tells he doesn't need Hulk but Banner, and tries to reassert himself with an ultimatum. This makes the Hulk laugh and turn back into Bruce Banner. Shortly later, Banner inoculates Hawkeye with an antidote, and turns into Hulk so both heroes can reach the Leader.

In Las Vegas, a captured Thor is brought to the Leader to serve as entertainment fighting Abomination. Thor calls Mjolnir but it turns to be the Leader's plan all along, as Absorbing Man touches the hammer and takes on its properties, then attacks Thor. Hawkeye and Hulk arrive, and while Hulk faces Abomination (who activates a Gamma enhancer on himself), Hawkeye shoots antidote arrows on the Avengers.

Absorbing Man seems to have the upper hand on Thor, until the God of Thunder reveals that now he can control Creel's moves just like he controls Mjolnir. The Leader activates a mech to face Hulk and Hawkeye, but Thor hurls Absorbing Man into smashing the mech and Hulk hurls the gamma emitter into space, collapsing the dome. After everyone is back to normal, footage from Hawkeye's sky cycle proves he was framed by Black Widow and he is offered to get back his work at S.H.I.E.L.D., but he refuses. Iron Man offers Hulk to return with the Avengers, which he accepts only if Hawkeye joins.

Meanwhile, Abomination is found by Baron Zemo and his almost complete Masters of Evil.

Trivia

 * Crimson Dynamo appears with the Masters of Evil with no explanation. The tie-in comic of the series tells how was he recruited.