The Avengers: Earth’s Mightiest Heroes! is an American animated television series by Marvel Animation in cooperation with Film Roman based on the Marvel Comics superhero team the Avengers. The show debuted on Disney XD in Fall 2010 starting with a 20 part micro-series.
Marvel Entertainment, LLC and Disney XD announced that a “new Marvel Universe” programming block named Marvel Universe which includes Season 2 of Avengers and the animated Ultimate Spider-Man series that began broadcasting in April 2012.
The series initially features a team based on the roster for the original Avengers, composed of Iron Man, Ant-Man, Hulk, Thor, and the Wasp. The team is later joined by Captain America, Black Panther, Hawkeye, Ms. Marvel, and Vision, while Spider-Man is named to reserve status. In terms of tone and style, the series is based primarily on the original stories by Stan Lee and Jack Kirby. However, it also tends to use material from all eras of the comic’s run and other sources such as the Marvel Cinematic Universe.
According to statements made by Loeb, Head of Marvel TV at 2012 SDCC, this series will “transition” into a new series entitled Avengers Assemble in 2013. Whether this means the new series will follow the continuity of Earth’s Mightiest Heroes or reboot it is presently unknown.
Since only two seasons are shown so the plot will told off those two;
As the world’s most dangerous super-villains break out of the Vault, the Cube, the Big House, and the Raft, five of Earth’s mightiest heroes assemble a crime fighting alliance called the Avengers. The Avengers’ team includes Iron Man as team leader, Ant-Man, Thor, The Hulk, and The Wasp.Captain America, Black Panther, and Hawkeye later join the roster. In the Season Finale, it is revealed that Thor’s brother Loki was responsible for the breakouts and had Enchantress form the Masters of Evil
Season Two depicts the Avengers as they track down the remaining members of the Masters of Evil and end up facing the invasions of the Skrulls in the first half of season and the Kree in the second half of the season. The Avengers are unaware that Captain America has been replaced by a Skrull as part of the infiltration of Earth. Season 2 also suggests a developing storyline that Surtur is gathering strength to oppose the Avengers. Ms. Marvel and The Vision join the Avengers. Many other characters from the Marvel Universe such as Spider-Man, Wolverine, Scott Lang, Heroes for Hire, Doctor Doom, Surtur, Crossfire, Thunderbolt Ross, his Red Hulk form, Guardians of the Galaxy, Falcon and Beta Ray Bill appear. Series producers Joshua Fine and Christopher Yost have revealed that certain returning characters will adapt their Ultimate Universe counterpart costumes, such as Nick Fury who returns in Season 2 appearing more like the Ultimate Universe Fury with a shaved head and goatee, and the Skrull who replaced Captain America wears the costume directly adapted from Ultimate Captain America and uses an energy shield.The second season premiere, entitled the “The Private War of Dr. Doom”(featuring Dr. Doom and The Fantastic Four) was shown to audiences at both the 2011 San Diego and New York Comic Cons; as well as the 2012 WonderCon in Anaheim. It premiered on April 1, 2012.