Middle school students fought fiercely against one another in a national tournament. Now, 50 chosen representatives return to fight again as high school students! 
The stage is the U-17 (Under Seventeen) Japanese Representative Training Camp. Middle school students have been invited for the first time to a camp known to produce the best Japanese tennis players. National champions from Seigaku, Hyotei, Rikkai, Shitenhoji... With all the rivals from the national tournament attending, everyone eagerly awaits their reunion. 
At first, the middle schoolers do not expect much from their high school opponents. However, the training camp is not so easy! Athletes with skills incomparable to those they previously faced and their mysterious coach appear before them. Faced with numerous demanding challenges, can the middle schoolers survive in this meritocratic training camp? 
(Source: Crunchyroll)