The neighboring families of Asakura and Uesugi have a close relationship, and the children from both families, Nanami (played by Masami Nagasawa), and the twin brothers Tatsuya (played by Shota Saito) and Kazuya (played by Keita Saito), have been good friends since childhood. Influenced by their parents, the three children have a deep passion for baseball, and they plan to step into the sacred ground of Koshien together. As they enter their teenage years, different feelings begin to blossom between the boys and girls. Younger brother Kazuya leads the team to Koshien, becoming a star at school. Nanami serves as the baseball team's manager, watching over her childhood friends every day. The older brother Tatsuya possesses even greater baseball talent than his younger brother, but after entering high school, he gives up baseball to join the boxing club. Who can understand the feelings entangled within? An unexpected event, however, changes the lives of the young boys and girls...