Elementary school programmer Raita Oozora finally completes and debuts FM sumo wrestler Shiko at the FMSUMO tournament, where mini sumo wrestlers are controlled by FM radio waves.

This is a completely new story with no relation to previous Gundam series. Set in the 21st century with Japan as the main stage where a mysterious army has invaded with super weapons called Mobile Suits, the protagonist stand against them with a mobile suit called "Gundam". The year is 200X. A mysterious robot fell from the sky into Tokyo. The robot is called a "Mobile Suit". Meanwhile, another Mobile Suit named "Gundam" crash landed near Kurono.

Twin daughters born into a count's family...one of them is destined to become the "devil's bride" even before she is born. The twins, who lived their days in peace without knowing anything about it, one day, their lives are ruined by the "devil's crest" that appears in the sister's hand--.... The younger sister, Luna, receives all the attention and love from her family, while her older sister, Ruthie, is isolated and looked down upon by no one. And the ugly feelings and desires of the people surrounding the twins.......Who will become the true "devil's bride"?