On the day of the mysterious space explosion, five sparks drop in a warehouse in Seoul. “The Five Hunters”, the strongest fighters in the universe, came to Earth to find “Cardia”, the heart of the universe, which was lost due to the attack of the space criminal group “Creature”. Meanwhile, children eagerly waiting for the new transforming robot toys they ordered for the club’s presentation are puzzled by the fact that the robots are old and broken. Furthermore, these robots are moving, talking, and fighting the villain of the universe. Children absolutely need robots for a presentation that is just around the corner, and “Five Hunters” also desperately needs their help in order to recover their damaged bodies caused by a fall on the Earth and carry out the mission safely. However, there is no proper communication between mischievous children and the space warrior robot, and it is not easy for the hunters, who are consistent with their arrogant warrior attitudes, to cooperate with children who cannot concentrate at all.
Those who have “Cardia”, called the heart of the universe, become the center of the universe and have the absolute power to move the whole creation freely. What was originally hidden in a place where no one knew was revealed to the world by the cosmic explosion caused by the “Creatures”. Due to this accident, Cardia deviated from its original location is currently missing. It is presumed that Cardia crashed somewhere in Seoul on Earth, but the exact location is unknown. In response, Creatures trying to conquer the universe by obtaining Cardia and Hunters trying to stop it and bringing Cardia back to its original state will head to Earth all together. Cardia is not constant in appearance because it can freely sync any machine or living organism, and it is difficult to track its whereabouts because it moves and wanders in an unpredictable way. Therefore, neither the Creatures not the Hunters can easily catch Cardia.
While the attacks of the “Creatures” chasing “Cardia” are getting stronger and more persistent, the body of “Five Hunters”, which has suffered from various problems on its way to Earth, does not recover easily. In response, Hunters finds a new solution called “Transformation and Unity”. However, it is necessary for humans to become robot controllers and cooperate. No one is more suitable for this job than children with the knowledge about transformation robots. However, the children are still too young and lacking in courage to carry out this enormous mission. The children and the Hunters gradually grow with faith and friendship toward each other, and they take courage to protect each other as well as the peace of the universe.