Avengers: Age of Ultron is a 2015 American action-adventure movie about a group of superheroes known as The Avengers, who battle an advanced Artficial Intelligence known as Ultron that plans to exterminate all of humanity. It is a sequel to the 2012 film The Avengers, and it is part of the larger interconnected "Marvel Cinematic Universe." It features a large ensamble cast including Robert Downey Jr., Chris Hemsworth, Scarlett Johansson, Mark Ruffalo, and Chris Evans.
The Avengers raid the eastern European country of Sokovia and capture villain Baron Von Strucker (Thomas Kretschmann) as well as the powerful scepter originally used by Loki (as seen in the previous film, The Avengers). They also encounter two superpowered twins- Pietro (Aaron Taylor-Johnson) and Wanda (Elizabeth Olsen). Wanda, who has the power to "hex" minds and implant visions, uses her power on Tony Stark/Iron Man (Downey Jr) to give him a vision of a shattered world full of dead Avengers.
Upon return to America Stark (inspired by his vision) works with Bruce Banner/The Hulk (Ruffalo) to use the scepter to develop an advanced Artificial Intelligence known as "Ultron." Stark envisions Ultron as a global defense system. Unfortunately, Ultron decides that the greatest threat to Earth is humanity itself, and sets about eradicating all humans. It is aided by Pietro and Wanda, who hold Stark responsible for the death of their parents. Wanda uses her powers on Hulk, Thor (Hemsworth), Black Widow (Johansson), and Captain America (Evans), causing Hulk to briefly go on a destructive rampage. The public backlash over the resulting Hulk-Iron Man fight sends the Avengers into hding.
Ultron, desiring a physical body, uses the power of Loki's scepter to take control of Dr. Helen Cho (Claudia Kim), turning her into his servant. She is successful in doing so, but when Ultron becomes a physical being, Wanda is able to read its mind and learns of Ultron's plan to kill all humans. She and Pietro switch sides and join the Avengers.
In a climatic battle, the Avengers manage to stop Ultron from raising Sokovia's capitol city into the air and dropping it back to Earth as a gigantic meteor to destroy humanity. The Hulk, Wanda, and the Vision (Paul Bettany) smash Ultron's body and destroy him for good.