Following the conclusion of the National Middle School Tennis Tournament, 12-year-old tennis prodigy Ryouma Echizen sets out to the United States in order to further improve his tennis skills. While finding his own way to shine in the sport, Ryouma investigates a perplexing development: the circumstances behind his father's retirement from professional tennis. Known as "Samurai Nanjiro," Ryouma's father Nanjiro is a legendary tennis player whose career abruptly ended after the US Open finals several years prior. Though Ryouma has studied the final match extensively, there are still many gaps in his understanding—gaps that he would only be able to fill by watching the match in person. As luck would have it, a supernatural phenomenon transports the young prodigy—and his unsuspecting classmate, Sakuno Ryuzaki—back in time to that very event. Although the events that occur before the game seem normal at first glance, the appearance of the mafia soon complicates the mystery behind the retirement. Despite the bad odds, Ryouma must do everything he can to unravel the circumstances and prevent his father's career from ending.

The very first Candy☆Boy episode. Twin sisters, Yukino and Kanade Sakurai, room together in the dorms at their high school, enjoying school life with their friends and one another. One day, Sakuya Kamiyama, an underclassman, seeks out Yukino, while Kanade learns from a friend that Sakuya has admired Yukino for a very long time. This innocent revelation sets into motion a chain of events that eventually lead to Yukino expressing her feelings for her sister.