A rescue from an after-school beating brings Ippo Makunouchi to the Kamogawa Boxing Gym, where his punches surprise the fighters. The timid teenager has spent years helping his mother run a fishing boat rental business in his father's absence. That demanding work has built considerable strength, though it has done little to protect him from daily bullying.
Mamoru Takamura, the rising boxer who intervened, gives Ippo his first brief training. In a practice match with the gifted Ichirou Miyata, Ippo earns the other boxers' respect and finds a rival. Gym owner and former boxer Genji Kamogawa becomes his coach as he begins an official boxing career. Against increasingly powerful opponents, Ippo must endure rigorous training, victories, and defeats while pursuing success in the ring.