As the opening credits roll, an abbreviated portrait of Ogami Itto's grim past as Shogunate Decapitator and the murder of his wife unfold, with Daigorō providing the narration. The story then drops us into a tense moment: two hooded samurai pounce as Ogami pushes Daigorō in a cart, and he fights them off, ending their threat with swift resolve.
Around a roadside fire, the memory deepens. Ogami recalls the brutal test he once offered the infant Daigorō: a life-or-death choice between Ogami's sword, which would bind Daigorō to a path of vengeance against the Shogun, or Daigorō's ball, which would mean death so he could rest with his mother in heaven. Daigorō chooses the blade, sealing his fate on a road of ambushes and blood. The very next day, Shogun’s officials bring an impossible demand: swear eternal loyalty or commit seppuku with Daigorō. Ogami refuses the oath and vows to fight his way to freedom, with Daigorō by his side, a vow that draws a direct line to the powerful Yagyu clan—the Shogun’s spies and assassins—who stand as the obstacle to their escape.
A dangerous duel follows when the Yagyu leader proposes a test of strength: defeat the leader’s son, Kurando, and freedom will be earned. Ogami accepts, enduring Kurando’s sunlit advantage and Daigorō riding on Ogami’s back. In a moment of cunning, Ogami lowers his head to expose a mirror bound to Daigorō’s forehead, reflecting the sun into Kurando’s eyes and blinding him just long enough for Ogami to sever Kurando’s head. The victory is hard-won, and the two fugitives press onward, never lingering in one place as the Shogun’s ninjas close in from every side.
As they travel, Daigorō recounts further danger: the Shogun’s other son, Lord Bizen, and his men have orders to kill them. Bizen’s armor-hiding under robes makes him a deadly adversary, but Ogami’s skill proves decisive. He lures Bizen into a stream, concealing his blade within the cart’s handrails and drawing Bizen into a trap that ends with Ogami’s counterstrike. The confrontation leaves Ogami wounded, yet the Yagyu daimyo watching from afar signals that their war is far from over. Ogami’s resolve hardens—he will strike at the Shogun’s power wherever it shows itself, both for Daigorō’s sake and for his own harsh code.
The objective hardens when the self-styled “Supreme Ninja,” a formidable female operative, receives orders to eliminate the pair. Lord Kurogawa is skeptical of such a gendered force and allows eight of the Supreme Ninja’s ninjas to face his best warrior, Junai. Though Junai cannot land a fatal blow against the women, the duel persists with brutal force, until Junai’s fate is sealed in a grim display of relentless aggression.
An unexpected mission comes next: Ogami is approached with an assassination request against Lord Kiru, the Shogun’s brother, in return for a thousand pieces of gold. Kiru is escorted by a trio known as the Masters of Death, a formidable force whose presence signals a dangerous collision of loyalties and treachery. The journey draws more assaults from the Supreme Ninja’s cohorts, but Ogami dispatches them each time with his signature precision. The clash with the Supreme Ninja herself culminates in a brutal exchange: she ensnares him with a weighted net and fishhooks, yet Ogami cuts free and she retreats, a tactical retreat that leaves the path forward precarious and personal.
As the danger escalates, Ogami and Daigorō confront a more organized threat: Lord Kurogawa’s entire ninja force descends upon them. Ogami sets Daigorō in a safe haven, then uses the cart’s spear blades in a daring display of weaponry, wounding many and trimming the threat down to a few. He collapses from blood loss, but Daigorō—ever loyal—returns water and offerings to his father, a small exchange of mercy in the face of brutality. The Supreme Ninja arrives later, but Ogami offers no mercy to the traitor she represents, choosing to move forward with his son in tow rather than kill her on the spot.
That night, Daigorō is lured away by a haunting song and seized by Kurogawa and the Supreme Ninja, suspended over a deep well. The sight of Daigorō endangered forces Ogami into a maximal display of resolve: he refuses to surrender and battles the conspirators. When the moment comes, he cuts the rope suspending Daigorō, rips through the fight, and defeats Kurogawa and his ninjas. He spares the Supreme Ninja and leads Daigorō away, leaving her to face the consequences of her failures and return to the Shogun to answer for them.
The fugitives board a ship carrying the Masters of Death toward a rendezvous with Lord Kiru, with the Supreme Ninja again aboard as an unseen observer. Rebels ignite a fire on the vessel, and the Masters of Death declare a chilling truism: they recognize Ogami but will not attack him and Daigorō as long as he does not threaten them or Kiru and then departs. With escape all but sealed, Ogami tears through the burning deck and launches himself into the sea with Daigorō and the Supreme Ninja in pursuit. He pulls them both to shore and delivers them to a fisherman's hut, stripping all three down to their basics to share body heat and survive. The Supreme Ninja discovers that Ogami’s mercy is not weakness, and that he will not allow her to kill him or his son. By dawn, Ogami leaves her there, a grim acceptance that she will have to return to the Shogun and meet her own end.
The Masters of Death escort Lord Kiru through a desert of shifting sands, where a hidden rebel force erupts from below, killing many and forcing the Masters to push Kiru forward to safety. Yet Daigorō stands in their path, and the Masters of Death finally confront Ogami in a climactic confrontation where one by one they fall. Ogami revels in the power he wields, pursuing Kiru’s caravan and cutting down the guards as he makes his final argument with the Shogun’s authority: the Shogun means nothing to him. With Kiru slain, father and son walk away from the carnage, the elder watching his son with a mix of pride and sorrow.
As they walk, Daigorō speaks with a quiet, haunting line, a final confession of longing and acceptance: “I guess I wish it was different ... but a wish is only a wish.” The camera lingers on a freeze-frame close-up of Daigorō’s face as he looks back, a moment of memory that lingers as the credits roll.
> I guess I wish it was different ... but a wish is only a wish
