The Seido baseball team is holding their summer training camp. The managers are working hard to prepare onigiri for them to eat. Sawamura is trying to eat natto, his least favorite food, in order to gain the stamina to pitch for nine innings without getting tired. The players are keenly interested in who will perform well in the training camp and earn a numbered jersey for the summer tournament. Will Sawamura, Furuya or Kawakami earn the right to wear the ace number?