In the year 2187, the planet Earth, is leading the human civilization to certain destruction, caused by global warming. As such people are unable to live on the Earth's surface so they created domed cities, but as time goes by, war and unstable land condition parted the dome cities and they lose contact with each other. Shu is a teenage boy from Datania, a school-type city dome controlled by Zero, a data program, with the help of his human assistant Nines, and later Berk. They forced the children who lived there to live and work as programmed using the reset system, which resulted in the children having no emotions, needs, or human instinct, like robots. The series began when Shu, who dreamt of seeing the ocean, escaped with his friends from Datania with the help from, Ein, May, and Dolly from The Returners, rebels of Datania who live underground. Shu goes with the Returners to find Amaroute, another dome city which they believed to be the better place to live. Along the journey, Shu explored the world he has never seen before, he also joined the Returners in fighting Zero and his men who are after DT, a special substance inside humans, which Shu and his Returner friends have. Arriving in Amaroute, the Returners realized that Amaroute was the same as Datania, and likewise, it is controlled by Zero, but assisted this time, by another clone of Shu. Shu then learns the purpose of Datania and Amaroute is for each to create a rocket that will transport Zero safely in to orbit before a generator that has been preventing global flooding breaks down due to neglect and the world is flooded in a huge tidal wave. After Amaroute falls, Shu and his friends return to Datania to defeat Zero and save both its citizens and the rest of the runners. The Rocket there cannot be completed in time, but Shu has the idea they instead turn it in to an Ark and ride out the flood before the tidal wave hits. Work is complete and everyone is loaded aboard, but a technical fault prevents it from being launched just as the generator preventing the flood finally breaks down, forcing Shu and his friends to work against the clock to free it. In a shock twist, the tidal wave strikes before the Ark is seen being released, leaving the fate of Shu and everyone on board uncertain to the viewer.