The X-Men send Wolverine into the past to meet with the younger versions of the X-Men in hopes to fight a war in two time periods. The survival of the species depends on the past to help change the events of the present.
I saw this is 3D, and I'm not sure it made a big difference, but this is a must see movie for the summer. Sometimes time-travel movies can get a little complicated but this movie does a pretty good job of keeping things straight. I enjoyed seeing the younger versions of the characters. it was a darker version of story than the previous films, and maybe a little more violent, but still a solid movie.