Megu is sent to Earth in her early teens, she is adopted by Mammi Kanzaki, a former witch who gave up her royal ambitions to wed a mortal. Mammi bewitches her husband and their two children, Rabi and Apo, into believing that Megu has always been the eldest child of the family. Under Mammi's tutelage, Megu learns to control both her abilities and impulses in order to prove her worthiness for the crown. This Rite-of-Passage subtext is continued throughout the series.

The Dr. Yamanoue, Director General of the Ministry of Science, creates a boy robot named Mars as the most powerful weapon to protect Japan. However, he is unable to develop the best cyber brain he needs, so he asks his rival, Dr. Kawashimo, who disagrees with him, to develop it for him. After incorporating it, Mars is finally completed, but Dr. Kawashimo's anger is aroused because Yamanoue had concealed the fact that Mars is a weapon. Mars himself, on the other hand, has just been born and knows nothing about the world or common sense, and is unable to distinguish between right and wrong.

Shigeto Ikehara's first original story set in the "Rockman" world, which he already had made various comic adaptations for. The setting takes design clues from the famicom game "Rockman 5" and gameboy game "Rockman World 4", while the story loosely adapts the Blues story from Rockman 3, a game Ikehara hadn't adapated in his previous manga.

Adaptation of the Game Boy video game, Rockman World 3.

Rockman World is based on the Game Boy game of same name. This tankoubon contains two chapters that adapt the first two Rockman World games, originally published in Comic BonBon Summer 1991 Special and Comic BonBon 1992 Summer Special respectively, in addition to maps and strategy tips for the two games they are based on.