Hyoutei Gakuen's strange (but impossibly wealthy) captain Atobe Keigo decides to throw a giant party for his friend and teammate Kabaji. He invites both friends and rivals. Together they participate in many different sports and events: dancing, swimming, soccer, a relay race, a haunted house, and more.—Anime News Network

Hyoutei Academy's excessively wealthy and prideful tennis captain, Keigo Atobe, decides to host a giant one-day inter-school festival in order to bring together the middle school tennis circuit. The festival exudes class and wealth, befitting its host. The extravagant occasion is filled with many attractions, with the most major event being a fierce relay race between all of the schools in attendance. However, Atobe has his own reasons for hosting this Super Tennis Festival; it seems that the special day is all for a certain someone among the festival attendees.—MAL Rewrite

Hyotei Gakuen's ridiculously rich and outrageous captain, Atobe Keigo, has organized a special event for the day - the first tennis carnival; all of the regional Junior High tennis teams, from St. Rudolph to Rikkaidai, have been invited. Held in a grand arena complete with haunted houses, variety acts, and sporting contests, from soccer to ping pong and food stands, this lavish carnival promises to be full of fun. However the main event of the day is an obstacle competition between the schools; and with their pride, and a set of high-class tennis equipment on the line, no one wants to lose. When it's neck and neck to the finish line, who will win, and just what is Atobe's true motive for organizing this day of events?—Anime-Planet

Hyoutei Gakuen's strange (but impossibly wealthy) captain Atobe Keigo decides to throw a giant birthday party for his friend and teammate Kabaji. He invites the rest of the Prince of Tennis cast. Together they participate in many different sports and events: dancing, swimming, soccer, a relay race, and more.—AniList