The plot of "Mega Man X6" takes place during the 22nd century where humans and intelligent robots called "Reploids" live together. The game follows shortly after the events of "Mega Man X5" in which planet Earth was devastated by an attack by the "Maverick" leader Sigma and the protagonist Zero sacrificed his own life to save it. As the world recovers, a Maverick known only as the "Zero Nightmare" has begun spreading chaos. Zero's comrade X, curious of its name, seeks out this new threat. Like past games in the series, "Mega Man X6" is an action-platformer in which the player tackles a series of stages and adds the unique weapon of each boss to X's arsenal.