A.D. 2087 - the United Lunar Empire Giganos wages war on the Earth Federation Military to take control of the planet and establish a "rebirth" of the human race. During an invasion of a colony by Giganos' forces, three civilian men stumble upon a trio of top-secret Metal Armor units called "Dragonars" and pilot them to combat the enemy forces.

The Abyss—a gaping chasm stretching down into the depths of the earth, filled with mysterious creatures and relics from a time long past. How did it come to be? What lies at the bottom? Countless brave individuals, known as Divers, have sought to solve these mysteries of the Abyss, fearlessly descending into its darkest realms. The best and bravest of the Divers, the White Whistles, are hailed as legends by those who remain on the surface. Riko, daughter of the missing White Whistle Lyza the Annihilator, aspires to become like her mother and explore the furthest reaches of the Abyss. However, just a novice Red Whistle herself, she is only permitted to roam its most upper layer. Even so, Riko has a chance encounter with a mysterious robot with the appearance of an ordinary young boy. She comes to name him Reg, and he has no recollection of the events preceding his discovery. Certain that the technology to create Reg must come from deep within the Abyss, the two decide to venture forth into the chasm to recover his memories and see the bottom of the great pit with their own eyes. However, they know not of the harsh reality that is the true existence of the Abyss. [Written by MAL Rewrite]

Mikura, Kurokawa, and Harada are the 3 members of the Danger Service Agency (DSA). Mikura is the brawns of the group, Harada is the brains, and Kurokawa is just a bitter ex-cop that likes to think he's in charge. They'll take on any job as long as it involves lots of danger and, of course, money. If you want to live long enough to eat dinner, you better not cross them. Their biggest case, however, could prove to be finding out why someone wants Kurokawa assassinated. (Source: ANN)

Mars is now almost entirely covered in water. Humanity exists in large city-ships that float through the open seas. But life is hard for those who live on Mars—the economy is in bad shape, work is scarce, and food is expensive and highly prized. Gram and his friends try to do the best they can, but the work keeps drying up. Some have taken to a life of piracy to combat the corruption in the government; one such group is the pirates of the feared Ship of Aurora. And the Earth government, which rules Mars, has dispatched a new team of military pilots to combat them. In their specialized mecha called Round Bucklers, they must make the seas of Mars safe for humanity. Caught in the wrong place at the wrong time, Gram finds himself on the run with the most notorious pirates on Mars. But here's the thing—he's starting to like them! (Source: Bandai Entertainment)