The full-length trailer for X-Men: Days of Future Past arrived today, and it delivers in double doses. Two Professor Xaviers, two Magnetos, a young/old Wolverine, plus a barrel full of mutants.

Days of Future Past, which opens May 23, 2014, picks up after the 2011 prequel X-Men: First Class, which gave us the backstories of the mutant superheroes as young people in the 1960s, as they discovered their powers and forged alliances.

Playing the young and old Professor Xaviers are James McAvoy and Patrick Stewart, while Michael Fassbender and Ian McKellan play the young and old Magneto. Hugh Jackman reprises his role as the cantankerous Wolverine, while Jennifer Lawrence is the young Mystique. Other mutants are Anna Paquin as Rogue, Nicholas Hoult as Beast, Ellen Page as Kitty Pryde, Evan Peters as Quicksilver, Shawn Ashmore as Iceman and Halle Berry as Storm. Peter Dinklage as Bolivar Trask — sporting a pornstache — rounds out the stellar cast.

The synopsis, from the Facebook page:

The ultimate X-Men ensemble fights a war for the survival of the species across two time periods in X-MEN: DAYS OF FUTURE PAST. The beloved characters from the original “X-Men” film trilogy join forces with their younger selves from “X-Men: First Class,” in an epic battle that must change the past – to save our future.

[youtube=http://www.youtube.com/watch?v=pK2zYHWDZKo]