After one of Twilight Sparkle's experiments goes wrong, the Cutie Mark Crusaders are switched with their other dimensional counterparts, the Destiny Mark Desperadoes . While the Crusaders and Desperadoes struggle to adapt, Princess Twilight tries to bring the Crusaders home. But not everything is as it first appears. The Desperado's home dimension is a brutal place, and all of its inhabitants have their own agendas. The only thing that anyone can be certain of is that Equestria just got a lot more dangerous.