Next Avengers: Heroes of Tomorrow is the fifth film in the Marvel Animated Features about the offspring of Earth's Mightiest Heroes battle against Ultron. It is a sequel to Ultimate Avengers 2 and prequel
A battle with Ultron leaves The Avengers defeated, with six of the heroes killed during the fight, and the world at the mercy of Ultron's machine army. Iron Man / Tony Stark is told by Captain America to take the Avengers' children to an underground fortified refuge hidden above the Arctic Circle. The children are James Rogers (son of Black Widow and Captain America), Henry Pym Jr. (son of Giant-Man and Wasp), Azari (son of Black Panther and Storm), and Torunn (daughter of the absent Thor and Sif).
Stark secretly raises and trains the children for 12 years. One day The Vision arrives at the refuge after hiding for over a decade from Ultron. He has come to inform Stark that Francis Barton,(son of Hawkeye and Mockingbird), is also alive.
While the curious children are eavesdropping on Stark and the Vision, James accidentally activates a series of Iron Man-style robots, called the Iron Avengers, that mimic the looks and abilities of Captain America, Hawkeye, Black Panther, Thor, Black Widow and Giant Man. Because they are programmed to defeat Ultron upon activation, they take off to do so, whereupon they are detected by Ultron's worldwide sensors, revealing the location of the refuge. Ultron proceeds to the refuge and invades it. Stark, now dressed as Iron Man, is able to stall Ultron long enough for the children to escape, but he is eventually subdued and captured. Ultron is also able to reprogram the Iron Avenger robots to follow his commands.
Sneaking into Ultra City to rescue Stark, the four young Avengers run into Francis Barton, Hawkeye's son. They decide to team up with him, and his group of resistance fighters, to rescue their guardian.
The five manage to escape with Stark from Ultron's trap in his citadel, and they head to the desert, along with an older Betty Ross, where Bruce Banner (The Hulk) has decided to hide out and keep away from other people for their own safety. After he refuses to help them, James comes up a plan to lure Ultron there so he can cause the Hulk to appear, destroying the robot.
The young Avengers fight a losing battle with the mechanical doubles of their parents, but they manage to awaken the Hulk, who defeats the Iron Avengers and ultimately destroys Ultron, ripping him in two. Ultron begins to rebuild himself, so Torunn decides to carry his body into space, throwing the two pieces in opposite directions, ensuring that he cannot rebuild himself. She nearly suffocates and freezes in the process, resulting in her father, Thor, rescuing her and explaining why he left her on Earth. Thor invites Torunn to join him in Asgard, but Torunn chooses instead to return to her family on Earth. As a parting gift, Thor sends her back to Earth in full Asgardian armor.
With Ultron finally defeated, the five young Avengers prepare to return to Ultra City, to deal with Ultron's remaining forces and rescue the populace.
- Noah C. Crawford as James Rogers (Captain America and Black Widow's son)
- Aidan Drummond as Henry Pym Jr. (Giant-Man and Wasp's son)
- Brenna O'Brien as Toruun (Thor and Sif's Daughter)
- Dempsey M. Pappion as Azari (Black Panther and Storm's son)
- Adrian Petrew as Francis Barton/Hawkeye II (Hawkeye and Mocking Bird 's son)
- Tom Kane as Ultron and Tony Stark/Iron Man
- Fred Tatasciore as Hulk, Additional Voices
- Ken Kramer as Bruce Banner
- Michael Adamthwaite as Thor, Additional Voices
- Shawn MacDonald as Vision, Additional Voices
- Nicole Oliver as Betty Ross, Additional Voices
To be added