"Avengers: Age of Ultron" arrives in theaters on May 1, 2015. ©Marvel

“Avengers: Age of Ultron” arrives in theaters on May 1, 2015.

(Relaxnews) – In the second movie on the Marvel superhero team, due in theaters next spring, the original protagonists are joined by a few newcomers.

Marvel and Disney revealed the official plot summary for “The Avengers: Age of Ultron” through the website Stitch Kingdom. In “the epic follow-up to the biggest Super Hero movie of all time,” as the studios’ release boldly calls the movie, Tony Stark (Robert Downey Jr) tries to revive a peacekeeping program, but things don’t go according to plan.

With the fate of the planet hanging in the balance, the superheroes Iron Man, Captain America (Chris Evans), Thor (Chris Hemworth), Hulk (Mark Ruffalo), Black Widow (Scarlett Johansson) and Hawkeye (Jeremy Renner) take on the dangerous mission of stopping the evil Ultron.

Samuel L. Jackson will reprise his role as Nick Fury, who along with Agent Maria Hill (Cobie Smulders) provides the Avengers with additional support. Newcomers to the franchise include James Spader as the robotic villain Ultron, along with Elizabeth Olsen and Aaron Taylor-Johnson as Magneto’s twin offspring Wanda and Pietro Maximoff, aka Red Witch and Quicksilver.

Paul Bettany, previously heard as the voice of Tony Stark’s digital personal assistant Jarvis in the “Iron Man” trilogy and “The Avengers,” appears in the sequel as the superhero Vision.

Helmed by Joss Whedon, who also directed the first movie, “The Avengers: Age of Ultron” arrives in US theaters on May 1, 2015.