Uma Musume: Cinderella Gray follows Oguri Cap, a young horse girl whose early promise on the racetrack has been overshadowed by setbacks and the pressures of expectation. Unlike the brighter, more idol-like tone of Pretty Derby, this story takes a more grounded and emotional approach, exploring the struggles, doubts, and determination of its characters.

As Oguri Cap navigates her training and competitions, the series also introduces other racers, each with their own motivations and personal challenges. Their interactions, rivalries, and friendships create a rich ensemble story, giving depth to the world beyond a single protagonist. Through perseverance, personal growth, and the quiet drama of racing, Cinderella Gray shows how ambition and passion shape these characters both on and off the track.