"Ryuoh no Oshigoto!" centers on Yaichi Kuzuryu, a 16-year-old professional shogi player who holds the prestigious title of Ryuoh, or Dragon King. Despite his young age, Yaichi is a seasoned player with a sharp mind and a somewhat aloof personality. His life takes an unexpected turn when he is approached by Ai Hinatsuru, a nine-year-old girl who claims to be his daughter from a past relationship. Ai, who idolizes Yaichi, aspires to become a professional shogi player herself and seeks his guidance.

Yaichi reluctantly agrees to mentor Ai, setting the stage for a story that intertwines the competitive world of shogi with themes of mentorship, personal growth, and familial bonds. As Ai begins her journey into the shogi world, she faces numerous challenges, including the skepticism of seasoned players and the pressure of balancing her studies with her passion for the game. Yaichi, meanwhile, grapples with his own responsibilities as a mentor and the complexities of his past, which gradually come to light as the series progresses.

The narrative explores the intricacies of shogi, often delving into the strategies and psychological battles that define the game. Through Ai's development as a player and Yaichi's evolving role as a teacher, the series highlights the dedication and perseverance required to excel in a highly competitive field. Supporting characters, such as Yaichi's fellow shogi players and Ai's classmates, add depth to the story, providing both comedic relief and moments of tension.

As the series unfolds, it balances the competitive intensity of shogi tournaments with quieter, character-driven moments that reveal the personal struggles and aspirations of its cast. The relationship between Yaichi and Ai serves as the emotional core of the story, evolving from a reluctant mentorship to a genuine bond built on mutual respect and shared passion for shogi. The series concludes with a focus on Ai's growth as a player and Yaichi's acceptance of his role as both a mentor and a father figure, leaving room for future possibilities in their intertwined lives.