Ueki no Housoku tells the story of the Battle of the Supernatural Powers, a tournament to decide who will be the next King of the Celestial World. Each candidate (100 in total) is required to choose a junior high school student to act as their fighter. Each student is given a unique power—the power to change one thing into something else. The winning King of the Celestial World Candidate will become King of the Celestial World and the winning student will receive the Blank Talent, a talent that can be anything they choose.