The government has long held mutants in general, and the X-Men in particular, in great suspicion. Over the years, various shadowy government agencies have tried to "control" the super-powered mutant population through the use of mutant-hunting robotic Sentinels. But now, a mysterious figure has risen effortlessly up through the corridors of power, and is manuevering the players on the board to his advantage.His name is simply Bastion, and his goal is nothing less than the exterminitation of all mutantkind. His means: a new breed of Prime Sentinel, half-human, half-machine engines of destruction that subvert their own humanity in the name of protecting it. The only heroes who dare stand in his Way: The X-Men. Long hated and feared by the world they are sworn to protect, these mutant super heroes have never before been against such a wall, never before have they been hunted and cornered as they are now. A war of Zero Tolerance has been waged against their kind, and their very existence is at stake.