As the Avengers (consisting of Captain America, Thor, Iron Man, Hulk, Black Widow, Hawkeye, and Vision) prepare for a party atAvengers Tower, it has comes to Captain America's suspicion that Iron Man has been acting strangely during the preparation of the party. After some investigation, it is discovered by the Avengers that Ultron has gained control of Iron Man's armor with the help of Yellowjacket and plans to take over the world.