During a race, mountain bike (MTB) enthusiast Shou Yamato is mysteriously dragged into another world alongside his friends, Kakeru and Makoto. Soon, the group discovers that this world known as "X-Zone" revolves around Idaten battles—MTB races characterized by special courses, rules, and hidden powers lying dormant within the bikes. The only way to return home is to win and obtain the MTB emblems from the defeated challengers.

Despite being perplexed and terrified of the bizarre world, Shou is surprisingly excited. He has the opportunity to compete with fellow MTB riders, make new friends and rivals, and also unearth the X-Zone's hidden truths that may dramatically change his fate. Shou and his friends must make it through an arduous journey, one rife with conspiracies against them, in order to safely return home together.