Marvel Ultimate Alliance 2 continues the four-player mayhem of the previous Marvel Ultimate Alliance and, before that, the X-Men Legends series. It is based on the Secret War and Civil War storylines from the comics. After Nick Fury leads an unauthorized super-hero assault on Latveria and a fight gone wrong kills hundreds of civilians in Connecticut, the government passes the super-human registration act, which requires all super-powered individuals to reveal their identities to the government. At one point in the story, you have to choose the pro or anti registration side and certain heroes will always be on one side or another, locking them out if you choose the other path. The game after this point changes depending on the storyline you choose.