Ryūsei Narukami is your typical NEET. He spends his days shut in his room playing video games without a care in the world, living a lazy life. But the truth is, Ryūsei used to be a powerful demon king in another world! So why not spend this new life doing whatever he wants? Except, he wasn't the only one reincarnated into this world. The hero who struck him down is here too—and she's a really cute high school girl?! Can Ryūsei survive reuniting with his foe in a new world, or will he find himself fighting even in this life?

Famous racehorses that have left behind worthy legacies, unique as they can be, are reincarnated as horse girls in a parallel world. In this life, they start their journey anew as they continue to race and perhaps relive the success they once lived through.

Aspiring to become the best racehorse in Japan, a horse girl named Special Week moves to Tokyo to enroll in the Tracen Academy—an institution that nurtures horse girls like her to become better racers. There, Special Week witnesses the sophisticated running style of Silence Suzuka and is inspired to become a racer like her. Shortly after, Special Week finds herself recruited into Silence Suzuka's team, Spica. From there, she begins her path to the top—one lap at a time.