The film will be the third instalment in the comic book franchise, which stars Robert Downey Jr as billionaire playboy and superhero Tony Stark.
The synopsis reveals that the movie will find Iron Man going up against an "enemy whose reach knows no bounds".
It reads: "When Stark finds his personal world destroyed at his enemy's hands, he embarks on a harrowing quest to find those responsible.
"This journey, at every turn, will test his mettle. With his back against the wall, Stark is left to survive by his own devices, relying on his ingenuity and instincts to protect those closest to him.
"As he fights his way back, Stark discovers the answer to the question that has secretly haunted him - does the man make the suit or does the suit make the man?"
Don Cheadle, Sir Ben Kingsley and Gwyneth Paltrow are also due to star in the picture.
A trailer for Iron Man 3 will debut later this month.
The movie's release date has been set for May 3, 2013.
Watch a featurette of Iron Man 2 below: