An old-fashioned, clumsy man arrives in a seaside town where the salty ocean breeze blows. His name is Aozora Kanjiro, a professional baseball player in his twenty-fifth season, with a single obsession: hitting home runs as far as possible. Nicknamed Lonely Blues, he finds himself on the verge of being scrapped, signing a precarious contract with the perpetually last-place Shonan Seagulls for a salary of 2.5 million yen plus performance bonuses. With three children in tow, Kanjiro moves to a coastal town for a fresh start. Almost immediately, he gets into a fight with the neighborhood association chairman and is ostracized. Every action he takes is chaotic, causing trouble for his family and teammates, yet he also shows surprising and endearing qualities. Kanjiro is a relic of the Showa era, a man whose values clash with the modern world, but he is determined to break through the stifling norms around him.

The story unfolds as a baseball-infused family comedy, blending slapstick chaos with genuine heart. Kanjiro's relationship with his children is central, as he tries to build a new life after the death of his wife, Natsumi. Her memory haunts him, and a promise he made to her before she died to hit a colossal home run that reaches the heavens serves as a driving goal. On the field, Kanjiro defies logic and expectations. He is brought in as a pinch hitter, and his blunt, stubborn style of play clashes with teammates and coaches but also inspires them. He stages a strike when demoted to the minors, gets into brawls, and trains struggling former major leaguers with bizarre methods. Off the field, he fights local thugs, rallies the town, and creates a stir wherever he goes, earning both resentment and grudging respect.

As the series progresses, Kanjiro faces increasingly significant challenges. He locks horns with data-driven baseball, embodied by coaches who rely on analytics, and battles against his own physical decline. The manga follows several notable narrative arcs: his unexpected chance to play in crucial games after twelve years without fielding, a grudge match against his former team, the Nagoya Pirates, and the arrival of a giant slugger named Bano Seisuke who idolizes him. At the climax, Kanjiro learns he has a wrist injury that threatens his career. Facing his final at-bat, he decides to retire and puts everything into one last swing, aiming to fulfill the promise he made to his wife. The story concludes with a moment of beauty and catharsis as he swings for the heavens, a fitting end for a man who lived by his own chaotic, romantic, and heartfelt rules.