Bumi, a 14-year-old boy, is stranded on a foreign planet, when the shuttle that transports him has an accident. He loses contact with his father and all he has is a device that repeatedly transmits his father's last messages. It tells that his father left him a castle at the end of the planet named Utopian. With the help of a dragon, Bumi finds the Utopian castle. What he does not know is that a sword symbolising the power of four kingdoms that were at war, is being kept in the castle. Nino, one of the kingdom's warlords thinks that Bumi has pulled out the sword and hence becomes the true ruler of the four kingdoms. So Nino tries to take over the castle. With the help of his friends, Bumi defends his new home.