In the late Edo period, a chain of mysterious arsons known as "foxfire" terrorizes the city of Edo. Amid this chaos, Matsunaga Gengo, once hailed as the "Fire-Eating Bird" and the greatest samurai firefighter in Edo, lives in obscurity as a ronin. Haunted by a traumatic incident from seven years earlier that forced his retirement and left him terrified of flames, Gengo spends his days in poverty with his sharp-witted wife, Miyuki.

His quiet life is shattered when an official from the impoverished Dewa Shinjo domain, Kishita Samon, appears with an unexpected offer: rebuild the domain's collapsed firefighting brigade. The Shinjo clan's firefighting group is in ruins. Plagued by political interference from the chief retainer Hokujo Rokuemon, who siphoned funds, the brigade has dwindled from 110 members to a mere 24. Their equipment is rotten, their morale is gone, and the people of Edo mock them as the "Ragtag Hawks" or "Boro Tobi-gumi" (tattered firefighters). With the encouragement of his wife and the desperate plea of the loyal Samon, Gengo accepts the challenge on a brutal condition: failure means death by seppuku.

Gengo, alongside the appointed vice-captain Torigoe Shinnosuke—a young man still reeling from his father's death in a suspicious fire—begins to rebuild from nothing. They recruit a group of outcasts and misfits, each with their own painful past. The hulking former sumo wrestler Torajiro, who lost his confidence after an injury, becomes the team's "breaker." Hikoya, a dashing acrobat and street performer on the run from debt, becomes their "flag-bearer" (matomochi). The brilliant but reclusive astronomer Kaji Seijuro, the son of Gengo’s former comrade, becomes their "wind-reader," a tactician who can predict the behavior of flames and wind. Together, this unlikely band of misfits forms the core of the reborn Shinjo fire brigade.

As Gengo trains his team and struggles to secure funding, Edo is plagued by the "foxfire" arsonist, a shadowy figure who sets sophisticated, devastating fires using gunpowder and explosive traps. The brigade must prove its worth not only by extinguishing infernos but also by uncovering the arsonist's identity. They clash with rival fire brigades, such as the elite Kaga Tobi, whose philosophy of protecting temples and shrines differs from Gengo's insistence on saving every human life. The narrative arc follows the team's growth from a mocked rabble into a respected, life-saving force, while Gengo confronts his own trauma and the mystery behind the fires that killed his predecessor and threaten to consume the entire city. The story builds toward the catastrophic Meiwa Fire, a conflagration orchestrated by the arsonist that forces Gengo and his team into their greatest and most desperate battle against the flames.