In the year 1461, western Japan is gripped by the devastating Kanshō famine, leading to the tragic deaths of 82,000 individuals due to resultant epidemics. During this tumultuous time, Nawa, the shōgun of Kyoto, imposes heavy taxes to sustain his extravagant lifestyle, while corrupt priests oppress villagers unable to repay their debts. Enter Hasuda Hyoe, a rōnin whose fate intertwines with that of Honekawa Doken, the chief of security in Kyoto and Hasuda's old comrade. Honekawa hires Hasuda to thwart an uprising in Yoshizaka, located in Kawachi Province, offering him 600 mon and Saizō, an orphan who was captured during a raid on a monastery led by Honekawa’s men.
After igniting tension by incinerating a customs station, Hasuda and Saizō successfully defend Yoshizaka from a bunch of bandits. Following this, Hasuda cautions the villagers about the shōgunate's awareness of their insurrection plans, advising them to remain patient while he devises a strategy to support their cause. Though Saizō is granted his freedom, he opts to align himself with Hasuda, eschewing the path of the ordinary for that of an insurgent.
The duo journey to Imazu, where Hasuda leaves Saizō to undergo a year of training under Master Karasaki, honing his skills with the bō and combat techniques. After their year apart, Hasuda reunites with Saizō, now armed with newfound skills, and discloses his intentions to lead an insurgency against the shōgunate in Kyoto, planning to launch their attack within the month. In a heart-wrenching exchange, Honekawa confronts Hasuda regarding his decision to lead this uprising, during which Hasuda recounts the extreme suffering he has witnessed under the shōgunate's rule. He asserts it's time to dismantle the oppressive system by declaring that he can obliterate the promissory notes and reclaim the women ensnared by the monasteries within just one hour.
As the word of the impending uprising spreads, more rōnin join forces with Hasuda and Saizō. In a strategic move, Hasuda sends a letter to Honekawa stating that the attack on Kyoto is set for 12 September at sunrise. However, this strategy backfires as Nawa commands his army to launch a massacre on Yoshizaka as a grim warning to any would-be insurgents. In a bid to protect his former lover, Ho-ōji, Saizō sends her a message the day before the attack, urging her to flee Sanjō to safety.
The insurgency astounds the city with a surprise attack at midnight instead of the anticipated sunrise, leading a formidable army of 10,000 through customs stations and arming every villager encountered on the way to Nijō. Utilizing directions provided by Hasuda at the great pagoda, the insurgents cleverly navigate around samurai forces. Upon reaching Nijō, they ignite flames in the monasteries and destroy the promissory notes, but soon find themselves encircled by samurai and Honekawa’s troops. In a dramatic moment, Hasuda and Saizō arrive to bolster their comrades during the fierce battle. As the insurgents revel in song and dance, Honekawa unjustly orders Hasuda and his army to vacate the city.
With the break of dawn, Hasuda, Saizō, and their followers advance toward Nawa's palace, where they face off against a drunken Nawa and Honekawa's forces. Initially overpowered, the insurgents regroup and counterattack as Saizō bravely eliminates Honekawa's army and Nawa's guards. In a moment of vengeance, a wounded Hasuda slays Nawa, avenging the villagers of Yoshizaka. The duo makes it to the main gate of the palace, erecting a sign labeled "outsider," symbolizing the conclusion of Nawa’s tyranny.
Later that day, Honekawa tracks down Hasuda and Saizō by the river, leading to a fatal duel where Hasuda pays the ultimate price. Surprisingly, Honekawa spares Saizō, exiling him from Kyoto for a decade. Fast forward five years into the future, during the tumultuous Ōnin War, Honekawa faces capture and execution at the hands of the Hosokawa clan. Meanwhile, after enduring his exile, Saizō reunites with Ho-ōji, hopeful for their future amidst turmoil and change.
