From Wikipedia:

The story is about Hyuma Hoshi, a promising young baseball pitcher who dreams of becoming a top star like his father Ittetsu Hoshi in the professional Japanese league. His father was once a 3rd baseman until he was injured in World War II and was forced to retire.

The boy would join the ever popular Yomiuri Giants team, and soon he would realize the difficulty of living up to the high expectations that came with such popularity. From the grueling training to battling his rival Mitsuru Hanagata on the Hanshin Tigers, he would have to take out his best pitching magic to met the challenge.