On a bridge late at night, Kotaro Katsura Akira Ishida is ambushed by a lone ronin. Katsura’s comrade, Elizabeth Shinji Takamatsu, pleads with the Yorozuya to help locate him. Shinpachi Shimura Daisuke Sakaguchi and Kagura Rie Kugimiya set out to find Katsura, while Gintoki Sakata Tomokazu Sugita accepts a separate assignment from Murata Tetsuya Takeharu Oonishi: retrieve the cursed sword Benizakura, which has been stolen and used to commit a string of grisly murders.
Shinpachi and Elizabeth soon come under attack from the assassin Nizou Okada Yutaka Aoyama, known to the Yorozuya as Nizo the Butcher, who claims to have killed Katsura and flaunts a hair he cut off as proof. Gintoki arrives to shield them, but the assassin and the sword’s dark power overwhelm him. In a tense moment, Shinpachi slices off one of Nizo’s arms, forcing him to retreat as the crowd gathers around the uproar.
Meanwhile, Kagura, aided by her loyal companion Sadaharu Mikako Takahashi, uncovers clues about Katsura’s whereabouts on a ship owned by the Kiheitai. The Kiheitai are led by Shinsuke Takasugi [Takehito Koyasu], and Murata Tetsuya [Takeharu Oonishi] is revealed to be acting as an accomplice who hopes to perfect Benizakura as a bioweapon. As Kagura digs deeper, Shinpachi and Elizabeth coordinate a plan to strike, while Murata’s machinations loom over the looming confrontation.
Shinpachi and Elizabeth locate Kagura through Sadaharu, and Shinpachi boards the Kiheitai vessel to rescue Kagura, with Elizabeth guiding Katsura’s faction in an assault on the Kiheitai. In the melee, Takasugi wounds Elizabeth, and Katsura—hidden aboard the ship in disguise as another Elizabeth—faces his former ally. Amid the chaos, Katsura detonates a factory, destroying all remaining Benizakura except for the blade Nizo holds. Katsura pledges to confront Takasugi again, and with Kagura and Shinpachi by his side, they prepare to square off against Kiheitai’s core members: Matako Kijima [Risa Hayamizu], the gunslinger, and Henpeita Takechi [Chafurin], the strategist.
Murata Tetsuko [Keiko Nemoto] then steps forward, presenting Gintoki with a new sword of her making to stand against Okada on the way to Kiheitai’s ship. Despite not being fully recovered, Gintoki remains in the fight, aided by the intensified, weapon-enhanced burst of Benizakura that tests Nizo’s body to its limit. The clash culminates in a fierce, life-or-death struggle, and a line of memory stirred within Gintoki surfaces as he endures the onslaught: > "the life or death confrontation [may have] awakened memories of battle that lay dormant inside of [Gintoki]."
Nizou is eventually consumed by the Benizakura and interrupts Shinpachi and Kagura’s efforts to help Gintoki. Murata Tetsuko’s sacrifice to protect her brother underscores the heavy cost of their schemes, and Gintoki, wielding Tetsuya’s blade, delivers the final strike to end Nizo and destroy Benizakura. In the aftermath, Takasugi unveils a broader vendetta: he intends to wipe out the Bakufu and reshape the world, allying with the amanto Harusame space pirates. Kawakami Bansai [Takumi Yamazaki], the Kiheitai’s fifth core member, joins the alliance, setting the stage for a ruthless pursuit of Gintoki and Katsura.
The groups eventually reunite and escape, vowing that the next encounter with Takasugi will be even more menacing and that there will be no mercy for their enemies.
Beyond the main story, the movie opens with a playful short where the Yorozuya introduce themselves in their trademark style, a gag that riffs on their “background-only” narration. It closes with a concluding short in which the cast shoots down ideas for a potential sequel, only to be interrupted by stand-ins for Warner Bros.—a spoof that pokes fun at the film industry, with the Yorozuya lamenting that their Gintama anime isn’t considered a “mega-hit” in Japan.
