"Panther's Quest" is the eleventh episode of The Avengers: Earth's Mightiest Heroes.
The Avengers check security footage to identify the man in black who once helped Captain America. Right then, the same man attacks the mansion and faces the Avengers, but suddenly surrenders and claims to be testing them. After introducing himself, Black Panther asks for help to overthrow Man-Ape as ruler of Wakanda. Captain America opposses, stating that if the people follow Man-Ape by free will it's their right to do so, but Black Panther explains that his people is stuck by tradition and Man-Ape won the rule by combat, but is a bad ruler. He also shows them that Man-Ape and his associate Ulysses Klaw are allowing HYDRA to mine Vibranium from the land. This convinces the Avengers to go.
Black Panther suggests a course that will avoid the Wakandan air defenses, but Iron Man, confident on the Quinjet's stealth capabilities, ignores him and the Quinjet is shot down. The Avengers regroup in the jungle floor below while Black Panther goes to confront Man-Ape alone, and Captain America is sent to watch his back.
Black Panther reaches Man-Ape's court and challenges for the rule of Wakanda, but Man-Ape, instead of facing T'Challa, sends his bodyguards against him. Meanwhile, the Avengers defeat a Wakandan army and reach the Vibranium mines where they find Klaw, Grim Reaper and some HYDRA agents. Klaw doesn't want the vibrations of the fight to cause the vibranium to explode, but Grim Reaper decides he has outlived his usefulness and a shot from his scythe causes Klaw to fall down onto overcharged Vibranium that, combined with the resonance from his sonic projector, causes him to transform into a creature of pure sound. Grim Reaper and HYDRA escape, but Klaw takes the Vibranium from them, so they leave empty-handed while the Avengers face Klaw.
Captain America saves Black Panther from the bodyguards and tells him to fight the Man-Ape while he stops anyone else. Black Panther has the upper hand until Man-Ape uses a miniature version of Klaw's sonic emitter to dsable T'Challa. However, the rage for his father's death gives T'Challa the willpower to overcome the sonic vibrations and defeat Man-Ape. Wasp distracts Klaw long enough to Iron Man and Ant-Man stop Klaw by containing his sound emitter (that had become the "heart" of the sound creature) inside a hollow Vibranium spike.
Later, Black Panther decides that the old ways allowed Man-Ape to take power, so he establishes a council to rule while he travels to America with the Avengers. Iron Man refuses until Wasp points he's the only one who can get them back home, so Black Panther is welcomed into the Avengers.
At the Cube, a Hulkbuster team investigate a strange green dome that is foming, but they are seemingly obliberated.
- Despite some heavy changes to fit the Avengers instead of the Fantastic Four, the basic elements of Black Panther's first adventure are still there: He tests the heroes by fighting them, then seeks their help against his father's murderer, they face Klaw who wants the Vibranium, and Klaw becomes a being made of sound.
- The final sequence in the Cube is sort of a preview to the following episode.