Following the completion of the National Middle School Tennis Tournament, Ryouma Echizen, a 12-year-old tennis prodigy, travels to the United States to develop his tennis talents. While pursuing his own path to success in tennis, Ryouma explores a strange development: his father's resignation from professional tennis. Ryouma's father, Nanjiro, is a great tennis player whose career ended abruptly after the US Open finals several years previously. Ryouma has studied the final match exhaustively, but there are still numerous holes in his comprehension that he can only complete by seeing the match live. As chance would have it, a strange occurrence sends the young prodigy—along with his unknowing classmate Sakuno Ryuzaki—back in time. It is now time for that event. Although the events leading up to the game look routine at first sight, the arrival of the mafia quickly compounds the mystery surrounding the retirement. Despite the odds, Ryouma must do everything in his power to untangle the circumstances and save his father's career.