The national idol unit "Fool's End" suddenly announced its dissolution. The group will hand over the "Tenka Bata," which can only be held by the best idols in the world, to a successor group. The successor group will be decided based on the total score of each group's music sales, live attendance, and merchandise sales. The race was named the "Battle Royale for the Tenka Bata," and it marks the beginning of a nationwide battle of the idols. At the Kawanakajima Festival, where the three groups NO PRINCESS, Lunatic Eyes, and "X-UC" were to perform, an incident occurred to a member of X-UC. Umino Risa, the youngest member of X-UC, is so anxious about the high level of performance of the other idols that she runs away. As a result, X-UC will have to go on stage with the nine remaining members. Then the announcement is made that this Kawanakajima festival will be the first battle of the "Battle Royale for the Tenka Bata"!

ウマ娘 プリティーダービー 3rd EVENT WINNING DREAM STAGE (Uma Musume Pretty Derpy 3rd EVENT WINNING DREAM STAGE) is event, which was held on August 28-29th 2021 at Tokyo Garden Theatre.