"G.I. Joe: Retaliation" is the sequel to 2009's "G.I. Joe: Rise of the Cobra". I must say that I thought "Cobra" was a terrible movie, so I was hesitant to even see the sequel, but I decided I should. The great news is "Retaliation" is 100x better then "Cobra". However, that doesn't mean the film was great.
To start off, you probably heard that this movie was delayed almost one year to be converted into 3D. Some say it was delayed for other reasons. But anyway, I didn't see it in 3D because it wasn't shot that way and I almost always hate 3D conversions. I have also heard from several people that it was terrible in 3D. So be cautious if your debating whether or not to see it in 3D.
But anyway, "G.I. Joe: Retaliation" follows the G.I. Joe's, who were framed for crimes against there country, the G.I. Joe team is then terminated by the President's order, and the surviving G.I. Joe's must face off against Zartan (the main villain in the film), his accomplices, and the world leaders he has under his influences. I should also mention that in "Retaliation" there are LOTS of new characters. Sometimes, there are actually too many new characters introduced at once.