Princess Nine, or Princess Nine Kisaragi Girls High Baseball Club, is a 26-episode Japanese anime which concerns the trials of nine girls at the Kisaragi School for Girls who form a baseball team for the purpose of playing on equal footing with boys' teams at the most prestigious high school tournament in Japan, The National High School Baseball Championship. Their aim to qualify for, and ultimately to win, the final rounds of the tournament which is held each year at the Koshien Stadium. They are led by ace pitcher, Ryo Hayakawa, a daughter of a former rising pitching star in Japan.