Long ago, B-Da City was attacked by an evil force known as the Dark B-Da (or dark beings) in their quest to control the entire Blue Solar System. The heroic B-Daman, drawing on their legendary powers and ingenious technology, managed to overthrow the Nol Arc Empire and restore peace to the universe. One thousand years later, the Dark B-Da have finally returned to conquer the Blue Solar System and make it part of their dominion. A young B-Daman named Shirobon, with a strong sense of justice, becomes a defender of B-Da City. Along with the help of his friends, they join the battle against the Dark B-Da, who have come to destroy their home!