Ark takes place on a dying alien world in which a global war between two technologically advanced human civilizations has reduced the planet to a wasteland. The only way to escape the world is by activating the Ark, an ancient giant robot capable of supporting a human city as well as traveling through space. (Source: Wikipedia)

In the year 2050 A.D, approximately 1/10th of Japan is now under water due to the global warming effect. The city of Tokyo was no exception. The economy of Japan is crippled from this disaster and the government is willing for anything to help revive the country. As a result, the Japanese government forms JESAS, a military foundation that has evil intentions of controlling Japan's future. JESAS handles the dumping of nuclear wastes into outer space. To insure their protection from other countries, JESAS has developed R.B. Robotic Weaponry, which is controlled by pilots with A.I. (Accurate Intuition). On the opposite side of the law is the Green Frontier, a united protection agency that was formed by countries sharing the same beliefs, to save the Earth. Featuring JESAS pilots Kanna and Kazuto and Green Frontier's Doota Kang and Mira Yu, these four youngsters will decide the fate of the Earth through love, friendship and the passion for their duty. (Source: AniDB)