Six months after the end of the first movie, Tony Stark (Robert Downey, Jr.) has used his Iron Man armor to bring about a negotiated peace treaty between the major super powers of the world, and his immense popularity with the general public is only furthered when he fulfills his father's dream by opening the "Stark Expo" in Queens, NY, to showcase all the latest inventions that will benefit the world. Stark is, however, still vilified by the United States government, and Senator Stern (Gary Shandling) in particular, who demands that he hand his armor technology over for military application. Stark refuses, publicly shaming rival Justin Hammer (Sam Rockwell) in the process by highlighting the failures of other people in their attempts to duplicate the technology, including Hammer, whose pilot snapped his spine when his suit turned 180 degrees in a "turn to the right" test.
All is not well in Stark's life, however: he has discovered that the palladium in the arc reactor keeping shrapnel from penetrating his heart (and that powers his armored suits) has begun to poison his body, slowly killing him, and all attempts to find a substitute element have failed. Slowly going off the rails as a consequence of what he believes to be his impending death, he appoints his former personal assistant Pepper Potts (Gwyneth Paltrow) CEO of Stark Industries, replacing her with Natalie Rushman (Scarlett Johansson).......