Zegapain

Long ago there was a battle between angels and humans, which ultimately ended with the angels’ retreat. Twelve thousand years later, the angels have become active again and have begun harvesting humans for nefarious purposes; and only the pilots of the ancient mecha known as Aquarion are able to oppose the angels' tools of war. The pilots have special powers, but the secret to defeating the Angels once and for all lies with the reincarnations of the two beings who defended humanity against the Angels in the past: Apollonius, an Angel who turned his back on his kind in order to protect humanity; and Siren, his human lover. Only Apollonius can awaken the true strength within Aquarion that is needed to defeat the angels; but who is the reincarnation of Apollonius?

At the dawn of the twenty-first century, a sudden climate change known as the Equatorial Winter devastated humanity. The survivors saw the new age as an opportunity to create a unified world order. Driven by this vision, the United Nations officially declared a war to determine which country would become the first world government, a war they named the Wisest World War. This conflict would be carried out not between soldiers but between individual mecha known as Gigantics. In such a restless world lives Shingo Suwa; he has just beaten hundreds of candidates to the position of pilot for Japan’s mecha – the Susanoo. But there is far more to the Gigantics than meets the eye. Is Suwa truly prepared for what it takes to fend off all the other champions and bring victory to Japan?

AD 2019: the giant mecha known as LINEBARREL falls to Earth, grabbing the attention of the anti-machina organization JUDA. Before JUDA can arrive on the scene, an unfortunate accident occurs: LINEBARREL crashes into Kouichi Hayase, a weak and frail pushover of a boy. Waking up underneath a beautiful naked woman, Kouichi discovers that he now possesses great power and can summon LINEBARREL for his own purposes. All Kouichi has wanted is to become a hero of justice and hold his own, instead his childhood friends Yajima and Risako fighting his battles for him – and now he finally has that chance. With LINEBARREL's power, Kouichi becomes cocky and aggressive, lashing out at those he cares about most; and as a 'hero of justice', Kouichi must find his new place in the world and protect himself from two organizations who want their hands on LINEBARREL.