Continue below to view the complete set of loglines for each episode of The Avengers: Earth's Mightiest Heroes. The guide is presented via production order, details provided by Marvel Animation, though each episode features airdate information.

Episode #27: The Private War of Dr. Doom
Original Airdate: April 1st, 2012
The Avengers and Fantastic Four are attacked by the forces of Doctor Doom, who have come to capture Wasp and the Invisible Woman. As the two teams fight to save New York from Doombots and rescue their teammates, they soon realize that there is more to Doom's attack than meets the eye.

Episode #28: Alone Against A.I.M.
Original Airdate: April 8th, 2012
Caught without his armor, Tony Stark faces A.I.M.'s latest creation, Technovore, a power-hungry monster. While Tony fights for his life, A.I.M. moves to steal the Iron Man armor itself, only to come face-to-face with Captain America, Black Panther and War Machine.

Episode #29: Acts of Veangeance
Original Airdate: April 15th, 2012
The Avengers hunt down the Masters of Evil only to find that the Enchantress is trying to take them down first. The Enchantress wants revenge on Zemo and his team for betraying her, and the Avengers find themselves caught in the middle.

Episode #30: Welcome to the Kree Empire
Original Airdate: April 22nd, 2012
An envoy from the alien warrior race, the Kree, visits Earth to determine if humanity is fit to join the ever-expanding galactic empire or be crushed in its path.

Episode #31: To Steal an Ant-Man
Original Airdate: April 29th, 2012
When Hank Pym's Ant-Man suit is stolen, he takes it upon himself to find the thief. Desperate to find his suit before it can put anyone in danger, Hank is pulled into a criminal underworld and caught in Crossfire's crosshairs.

Episode #32: Michael Korvac
Original Airdate: May 6th, 2012
The Avengers attempt to protect a mysterious man named Korvac from strange aliens that pursue him, but they soon realize that these aliens are the heroic Guardians of the Galaxy and that it is not Korvac who needs protection, but the Earth itself.

Episode #33: The Ballad of Beta Ray Bill
Original Airdate: May 20th, 2012
While searching for the fire demon Surtur, Thor is attacked by a powerful creature known as Beta Ray Bill, and the unthinkable happens when Bill lifts Thor's hammer as the two battle. Thor must ally himself with this strange warrior to save Asgard before Surtur and his demon army burn it to the ground.

Episode #34: Who Do You Trust?
Original Airdate: May 13th, 2012
The Avengers are torn apart when Nick Fury returns and reveals that the shapeshifting alien Skrulls have begun infiltrating Earth. The situation becomes worse when they learn a Skrull lurks within the Avengers.

Episode #35: Prisoner of War
Original Airdate: July 1st, 2012
After being held prisoner for months by the shape-shifting aliens known as the Skrulls, Captain America realizes he must align himself with his enemies in order to break out. Cap must warn the Avengers about the pending alien invasion but did not expect to face the Super-Skrull!

Episode #36: Nightmare in Red
Original Airdate: June 24th, 2012
When S.H.I.E.L.D. comes under attack by the Hulk, the Avengers rush to the scene and find a rampaging Red Hulk. The hunt is on for Bruce Banner as the Avengers try and unravel the mystery of who the Red Hulk is.

Episode #37: Infiltration
Original Airdate: July 8th, 2012
The shape-shifting aliens known as the Skrulls begin their invasion of Earth, starting with Wakanda, and only Ms. Marvel is there to stop it. Ms. Marvel must now fight enemies who look just like her friends. Meanwhile, Iron Man gets some help in detecting the Skrulls from an unlikely source.

Episode #38: Secret Invasion
Original Airdate: July 15th, 2012
The Avengers reunite to face the full power of the Skrulls as the alien invasion hits Earth. Captain America, Thor and Iron Man lead the charge against an army of Super-Skrulls, whose shape-shifting ability allows them to imitate the powers of any hero on Earth.

Episode #39: Along Came A Spider...
Original Airdate: July 22nd, 2012
The entire city has turned against Captain America in the aftermath of the Skrull invasion. When the Serpent Society attempts to prevent Viper from captivity, New York is put in the crossfire with only Captain America and Spider-Man to save them.

Episode #40: Behold ... The Vision
Original Airdate: July 29th, 2012
Now that the threat of alien invasion is over, Captain America does his best to restore hope to the world by rallying what is left of the Avengers. Together, the remaining members travel to Wakanda to repair Cap's shield, only to find a mysterious caped figure who plans to take the shield for himself.

Episode #41: Powerless
Original Airdate: May 5th, 2013
*The episode originally debuted September 25th, 2012 on home video*
Loki remains a prisoner of the Midgard Serpent for his crimes against Asgard. He smoulders with hatred for the Avengers, until the Enchantress offers him a chance at revenge. Can the Avengers regain their powers in time?

Episode #42: Assault on 42
Original Airdate: August 5th, 2012
When Whirlwind is captured, he is escorted to his quarters in 42, Hank Pym's confinement facility in the Negative Zone, by Captain America, Wasp and Ms. Marvel. 42 is virtually impossible to break out of, yet when they get there, they find that something is trying to break in.

Episode #43: Ultron Unlimited
Original Airdate: August 19th, 2012
The Avengers are attacked by robotic versions of themselves as part of Ultron’s plan to replace humanity. Each team member is captured one by one until Captain America stands alone against Ultron and his synthezoid Avengers.

Episode #44: Yellowjacket
Original Airdate: September 9th, 2012
Wasp and Iron Man try to persuade Hank Pym to rejoin the Avengers, but he is obsessed with his experiments and driven by guilt over Ultron. Meanwhile, Yellowjacket, a new vigilante, emerges and has his sights on eliminating the Serpent Society.

Episode #45: Emperor Stark
Original Airdate: September 16th, 2012
Vision awakens after a month of repairs only to find that Iron Man and the Avengers have taken over the Earth. With the whole planet against him, Vision must get to the bottom of Tony Stark's 'utopia' and come face to face with the power of the Purple Man.

Episode #46: Code Red
Original Airdate: September 23rd, 2012
Mysterious fumes in the Avengers' mansion cause everyone to suddenly feel sick, including the civilians outside. Luckily, Iron Man's suit is sealed off from the danger, so he must try to figure out what is going on before the Secretary of Defense, Dell Rusk, shuts down the Avengers.

Episode #47: Winter Soldier
Original Airdate: September 30th, 2012
Winter Soldier, Red Skull's top recruit, disobeys orders and saves Captain America's life.

Episode #48: The Deadliest Man Alive
Original Airdate: October 7th, 2012
In the midst of the alien Skrull invasion, Captain America convinces Hulk to transform back to Bruce Banner and turn himself in to General Ross and the U.S. Government for a crime he didn't commit - an attack on the S.H.I.E.L.D. Helicarrier caused by Red Hulk. When the Skrull threat is over and Bruce Banner's name is cleared, Bruce seeks revenge.

Episode #49: New Avengers
Original Airdate: October 14th, 2012
When Kang the Conqueror traps the Avengers in a temporal void and begins to bring his armies to the 21st century, Iron Man activates the New Avengers protocol and a new team is forged with Spider-Man, War Machine, Wolverine, Iron Fist, Luke Cage and the Thing. The New Avengers must defeat Kang to rescue the Avengers and save the world.

Episode #50: Operation: Galactic Storm
Original Airdate: October 21st, 2012
The alien Kree arrive to create a wormhole linking Earth's solar system to theirs, tearing the sun in half in the process. The Avengers must head into space and face the full might of the Kree empire in order to save the sun.

Episode #51: Live Kree of Die
Original Airdate: November 4th, 2012
The Avengers' space adventure concludes in a crash landing on the alien Kree homeworld, Hala, but Captain Mar-Vell's homecoming isn't very welcoming. Outnumbered, the Avengers' only hope is to convince the Supreme Intelligence, the ruler of the Kree Empire, that humanity is worth saving.

Episode #52: Avengers Assemble
Original Airdate: November 11th, 2012 (Series Finale Episode)
The Avengers have fought super villains, dinosaurs, time-travelling conquerors, and shape-shifting aliens, but that all pales in comparison with the arrival of the insatiable Galactus and his awe-inspiring heralds. In order to save the world, the galaxy and the universe, the Avengers have to rely on all the help they can get.