"Uma Musume: Pretty Derby - 1st Anniversary Special Animation" is a short anime special that celebrates the first anniversary of the "Uma Musume: Pretty Derby" franchise. The story is set in a world where anthropomorphized racehorses, known as "Uma Musume," compete in races while also pursuing careers as idols. The special focuses on the daily lives and interactions of the Uma Musume at Tracen Academy, a training institution where they hone their skills in both racing and entertainment.

The narrative centers on Special Week, a cheerful and determined Uma Musume who dreams of becoming the top racer in Japan. Alongside her are her friends and rivals, including Silence Suzuka, a reserved and talented racer; Tokai Teio, a spirited and ambitious competitor; and Mejiro McQueen, a confident and elegant performer. The special highlights their camaraderie, training routines, and preparations for an upcoming race event. It also delves into their personal struggles and aspirations, such as Special Week's desire to prove herself and Silence Suzuka's efforts to overcome past injuries.

The plot is interspersed with lighthearted moments, showcasing the Uma Musume's idol activities, including singing and dancing performances. These segments emphasize the dual nature of their careers, blending athleticism with entertainment. The special also introduces new challenges, such as the arrival of a rival team, which adds tension and motivation for the main characters to improve their skills.

Throughout the story, themes of perseverance, teamwork, and self-discovery are explored. The Uma Musume face setbacks and doubts but ultimately find strength in their friendships and shared goals. The special concludes with a celebratory tone, reflecting on their growth and achievements over the past year while looking forward to future endeavors. The animation serves as both a recap of the franchise's journey and a tribute to its fans, encapsulating the charm and appeal of the Uma Musume universe.