"Chivalry of a Failed Knight" is set in a world where individuals known as Blazers possess the ability to manifest weapons called Devices and wield supernatural powers. The story takes place at Hagun Academy, a prestigious institution training Blazers to compete in tournaments and hone their skills. The protagonist, Ikki Kurogane, is labeled the "worst one" due to his lack of inherent magical ability, despite his exceptional swordsmanship and determination. His life changes when he encounters Stella Vermillion, a foreign princess and a prodigious Blazer ranked at the top of her class.

The narrative begins with Stella challenging Ikki to a duel after a misunderstanding involving their living arrangements. Despite the odds, Ikki defeats Stella, earning her respect and admiration. Their relationship evolves from rivals to partners, and they form a deep bond, eventually becoming romantically involved. The story explores their growth as individuals and as a couple, as they navigate the challenges of their academy life and the competitive world of Blazers.

Throughout the series, Ikki and Stella face numerous adversaries, including fellow students, powerful Blazers, and political factions. Ikki's underdog status and his relentless drive to prove himself serve as central themes, while Stella's struggle to balance her royal responsibilities with her personal ambitions adds depth to her character. The series also delves into the dynamics of other students at Hagun Academy, such as Shizuku Kurogane, Ikki's younger sister, and Alice, a mysterious and skilled Blazer with her own agenda.

The plot is driven by the Seven Stars Sword Art Festival, a high-stakes tournament where Blazers compete for prestige and power. Ikki and Stella's participation in the tournament becomes a focal point, as they face formidable opponents and uncover hidden truths about the world of Blazers. The series blends action, romance, and political intrigue, with a focus on character development and the evolving relationships between the main cast. Themes of perseverance, self-worth, and the pursuit of one's ideals are woven throughout the narrative, making "Chivalry of a Failed Knight" a compelling exploration of its characters' journeys in a competitive and magical world.