Mega Man: 21XX Apocalypse is a conceptual strategy game that takes place in an alternate reality from 21XX. Here, Dr. Cain has not found Mega Man X, and thus Reploids were not created. Without Sigma and X, no one is able to stop Zero when he appears out of nowhere. A short time later, machines start going out of control, and after some months the whole continent is in chaos. No one knows what is going on, but being that Zero is the responsible, humanity begins contermeasures to destroy the red menace. Although Zero had not left the continent, machines began going out of control worldwide, and it was ordered that all robots must be shutdown.