Brilliant scientist Dr. Light conceived the construction of fully-operational human-like experimental robots to perform specific everyday duties. Dr. Light, and his assistant Dr. Wily, encouraged by their very first near-human robot - Mega Man - proceeded to develop six additional Humanoids, all programmed to perform prescribed rituals.
But, with the exception of Mega Man, all of Dr. Light's near-human robot experimentation went awry. Assistant Dr. Wily turned disloyal, re-programming Dr. Light's Humanoids, now bent on destroying opposition so Dr. Wily could control the world and its resources.
Resisting re-programming, Mega Man is chosen as the defender of the universe and its inhabitants. Mega Man dares to single-handedly penetrate seven separate empires of Monsteropolis, eliminating the leaders and followers of these sovereignties.