In the late Edo period, fire is one of the deadliest threats to daily life in Edo, and the samurai firefighters known as hikeshi are the city's first and last line of defense. Matsunaga Gengo was once celebrated as the finest fire-fighting samurai in all of Edo, a man called the Hikuidori, or Fire-Eating Bird, for his fearless feats in the heart of raging blazes. But a traumatic incident in a great fire left him unable to face the flames. He abandoned his post and spent five years in poverty as a ronin, living with his wife Miyuki and relying on her sharp financial sense to scrape by.

Gengo's quiet exile is shattered when a samurai from the impoverished Shinjo Domain, Samon Orishimo, arrives at his door with an urgent plea. The domain's fire brigade has collapsed: funds are nearly nonexistent, morale is shattered, and the few remaining men wear tattered coats that invite mockery. The citizens of Edo derisively call them the Boro Tobi-gumi, the Raggedy Firemen's Group. Tasked with rebuilding this broken organization as its new chief, Gengo accepts the challenge despite the near-impossible odds, spurred by Miyuki's encouragement and his own lingering sense of duty.

The brigade Gengo takes over is a hollow shell. The former chief was forced to commit suicide after clashing with the domain's powerful senior retainer Rokuemon Hojo, who had slashed the firefighting budget while demanding a showy front. Gengo's only ally is the young deputy chief Shinnosuke Torigoe, a cheerful and sharp-witted boy blessed with a photographic memory and hidden swordsmanship skills. Together, they set out to find capable men willing to join a laughingstock outfit.

One by one, Gengo recruits a team of misfits, each carrying their own past wounds. Torajiro is a fallen sumo wrestler with immense physical strength, haunted by a losing streak and the need to support his mother. Hikoya is a nimble acrobat who becomes the brigade's flag-bearer, a man who lives for the thrill of danger. Seijuro Kaji is a reclusive scholar who can read the flow of wind and weather with remarkable precision, a skill invaluable for predicting how a fire will spread. Gengo, with his exceptional hearing, strategic mind, and talent for recognizing hidden potential, forges these outcasts into a unit. He trains the raw recruits himself, while Miyuki uses her extraordinary arithmetic and negotiating skills to stretch their meager budget far beyond its limits.

As the newly formed Boro Tobi-gumi begins to prove itself on the fireground, winning grudging respect from the people of Edo, a darker threat emerges. A series of suspicious arsons, blamed on a mysterious figure known as Fox Fire, plagues the city. These fires are not accidents; they are tools of vengeance and hidden conspiracies. Gengo and his team find themselves fighting not only towering infernos but also the political scheming within the Shinjo Domain and the criminal plots that use fire as a weapon. The narrative arc builds toward the historic Great Meiwa Fire, a catastrophic blaze that threatens to consume Edo itself, forcing the ragtag brigade to confront the source of the arsons and the truth behind Gengo's own traumatic past. Through every blaze, the men who were once cast aside rediscover their pride, their bond, and the unyielding will to protect life at any cost.