In 2018 a young boy named 21 Emon dreams of becoming a space pilot and exploring space in general. He is the heir to a long line of hotel owners, which dates back to the founder of during the Tokugawa shogunate. Since the Earth has become a planet visited by tourists from all over the space, 21 Emon has to help out his family's business or they'll go bankrupt.

Tales of old speak of the legends of Excalibur, a sacred sword. The sword is wielded by those who are worthy of its power, bestowing them extraordinary strength and granting them the title of Arthur. However, a divine miracle results in the creation of multiple Excaliburs, thus distorting the fabric of time. Aiming to revert time to its original course, a group of six Arthurs composed of Danchou, Renkin, Kakka, Yamaneko, Tekken, and Rurou are sent back in time when the abnormal Excaliburs were spawned. They are assigned with one sole task: to destroy the Excaliburs of the past—all of which total up to one million. [Written by MAL Rewrite]

Doris Ruridou is young princess who had just entered Teito Academy. She is also a Panzer, a person with special abilities and fights with a weapon called a "tool". Shortly after entering, her older sister shows up to teach her how to fight as a Panzer against other Panzers who challenge her. (Source: ANN)

In the not so distant future much of the earth has been submerged under the sea or destroyed by earthquakes. At the center of the turmoil is the mysterious Orphan. Orphan may or may not be the original cause of the cataclysms. Orphan`s goal is to raise a ship hidden deep beneath the sea to the surface, but doing so would result in the destruction of all humans except for the small number which are loyal to Orphan. Orphan`s agents pilot mysterious mecha known as Grand Cheres, and search the world for mysterious, giant disks which occasionally appear, flying at high speeds and wrecking much of the countryside, or cities, when they hit the ground. After a dying disc almost kills Hime, a Brain Powerd is born from the disc. Brain Powerds are another type of Mecha, similar to but not the same as Grand Cheres. Hime becomes the Brain Powerd`s pilot, forming a symbiotic relationship with the living mecha and joins an International Organization dedicated to stopping Orphan, or at the very least saving humanity should Orphan succeed.