In 22nd century, world's continents are submerged under the sea except one land. The place is called Tera where a strong king with a tender heart, Tyron reigns: accepting everyone equally. Tyron's son, Kai respected his father and grew up with any concerns. However, in a coup, Kai's mother and even Tyron who was trying to protect Kai were killed by a pirate named Cler. Kai and his sister Luka managed to escape Tera ... and 10 years has past. A young pirate Kai Redian challenges to recover Tera togather with his company.