No sooner have Pete Wisdom and X-Force arrived in San Francisco than a massive wave of energy knocks them off the road. In the 1950's, in an effort to study the potential outcomes of a war between humans and mutants, a black-ops intelligence agency prepared to enact a small-scale test in the city, using a bioreactor to trigger latent mutations and spike aggression.
But now that experiment is active, leaving X-Force in a war zone as the only chance to save the city from destroying itself.
