Since childhood, horse girls Kitasan Black and Satono Diamond have admired and aspired to be like their fellow horse girl named Toukai Teiou. Chasing their dreams, they enroll in Tracen Academy, an institution dedicated to training horse girls and preparing them for legendary races. Soon after, Kitasan Black lands on Team Spica, the same team as Teiou. Beaming with motivation, she remains undefeated until she fails to win her first Grade 1 (G1) race—the most prestigious type of race in the league—but she is determined to unleash her true potential as a horse girl. Meanwhile, Satono Diamond comes from a long line of horse girls who, despite sporting incredible running prowess, have never won a G1 race. It is up to her to finally break this curse and bring the Satono clan the glory it deserves.