The main character of the story, Sei Iori, is a young Gunpla builder who loves Gunpla and dreams of entering the Gunpla Battle World Tournament.
With the introduction of this revolutionary Battle System, its popularity has expanded to the point that a Gunpla Battle World Tournament is held each year.
When he meets Reiji, a mysterious boy with superb Gunpla control skills, they team up to take on the World Tournament.