As the Avengers find a way to return Iron Man to their reality without bringing Ultron along, they managed to prevent Ghost from stealing Stark Industries technology at the Stark Expo. After swiping the prototype Arc Reactor, Leader head to the Wakandan Consulate to steal the Vibranium there with his army of Humanoids. When a guilt-ridden Thor helps Black Panther take down Leader when the Avengers arrive, Leader summons his new incarnation of the Cabal (consisting of Arnim Zola, Enchantress, Executioner, and Kang the Conqueror) to fight the Avengers while taking advantage of Iron Man not being there.
s04e01 - Avengers No More - Part 1
s04e02 - Avengers No More - Part 2
s04e03 - The Sleeper Awakens
s04e04 - Prison Break
s04e05 - The Incredible Herc
s04e06 - Show Your Work
s04e07 - Sneakers
s04e08 - Why I Hate Halloween
s04e09 - The Once and Future Kang
s04e10 - Dimension Z
s04e11 - The Most Dangerous Hunt
s04e12 - Under the Spell of Enchantress
s04e13 - The Return
s04e14 - New Year's Resolution
s04e15 - The Eye of Agamotto (1)
s04e16 - The Eye of Agamotto (2)
s04e17 - Beyond
s04e18 - Underworld
s04e19 - The Immortal Weapon
s04e20 - The Vibranium Coast
s04e21 - Weirdworld
s04e22 - Westland
s04e23 - The Citadel
s04e24 - The Wastelands
s04e25 - All Things Must End
"Marvel's Avengers Assemble" reunites the most popular super hero team - Iron Man, Hulk, Captain America, Thor, Hawkeye and Black Widow, along with newcomer Falcon, marking the first time in animation history this distinct team of heroes will join forces.
Led by Iron Man, the heroes train and live together in their new headquarters in Avengers Tower. The planet's most dangerous villains don't stand a chance when the Avengers assemble - whether they are stopping Dr. Doom from conquering Asgard, Attuma driving the Atlantean Army into New York City or Dracula unleashing vampire hordes, the Avengers must work together to succeed.