In 1926 Tokyo, steam power has become the city’s core energy source, fueling both industry and everyday life. At the Grand Imperial Theater in Ginza, the Imperial Combat Revue operates as a cover for a hidden mission: the Flower Division—a skilled circle of women who defend Tokyo from demonic threats using steam-powered mechs called Koubu-Kais while secretly performing as a theater troupe. The core members of this group are Sakura Shinguji, a disciplined swordswoman; Sumire Kanzaki, the charismatic lead actress; Maria Tachibana, a former Russian-ex-soldier with a stern heart; Iris Chateaubriand, a French telekinetic with a sharp wit; Kanna Kirishima, a Ryukyu karate expert; Kohran Ri, the inventive mind behind their machines; Orihime Soletta, a Japanese-Italian aristocrat whose elegance masks formidable resolve; and Leni Milchstraße, a German dancer whose grace hides lethal precision. Supporting them are other key figures such as Haruyoshi Tanuma, Kouran Li, and the rest of the ensemble, all united by a mission that blends spectacle with survival.
As Christmas approaches, the Flower Division receives a new, unexpected recruit: Ratchet Altair. Coming from New York City, Ratchet joins the troupe with a mission of her own—to establish a similar division in New York, pushing the group to broaden its reach while the city faces a fresh demon assault that very night. The Flower Division watches as some of the demonic forces are seized by the Japhkiels, unmanned mecha that hide their true demonic forms behind a façade of mechanized tech. This glimpse foreshadows a changing balance of power as the theater’s operations become entangled with covert warfare.
The division endures a string of brutal battles, with setbacks that shake their confidence. In one devastating clash, Orihime and Leni’s Koubu-Kai models are destroyed and replaced by Eisenkleid units, signaling a shift in the balance of force. Behind the scenes, Brent Furlong and Imperial Army officer Haruyoshi Tanuma leverage their influence to seize control of the Imperial Combat Revue’s command structure. They capture commander Ikki Yoneda, seize the theater, and place the Flower Division on indefinite standby, along with their assistant Kaede Fujieda and the Moon Division, under house arrest. Amidst these upheavals, Brent Furlong’s nearly immortal lieutenant, Patrick Hamilton, manipulates Orihime into becoming his ally, weaving a dangerous strand of betrayal within the ranks. Maria, investigating the Douglas-Stewart corporation, uncovers the Japhkiels’ true forms and confronts Hamilton—a man she briefly knew during her time as a mafia hitwoman in New York. Although gravely wounded, she escapes and keeps faith with the fight.
With the theater under lock and the Flower Division sidelined, Sakura and her comrades hatch a bold plan to retake their home. They mount a counterattack to seize back their Koubu-Kais and free Kaede Fujieda and the Wind Division from their captors. Ratchet’s more violent approach, however, strains the team’s unity, creating tension as Sakura seeks to keep the group focused. In a decisive turn, they liberate their allies and assault the theater again, confronting the demonic threat head-on. The Flower Division employs the Imperial Capital Barricade Formation to disintegrate the enemy forces, a gleaming testament to their combined strength and the power of their synchronized teamwork.
Yet the confrontation spirals into a chaotic showdown. Orihime is momentarily endangered by Hamilton’s machinations, and Leni intervenes to prevent Ratchet from killing Orihime, choosing to break Hamilton’s hold over her rather than let tragedy unfold. This pivotal moment allows Orihime to be freed from Hamilton’s control, though Leni and Orihime’s Eisenkleids suffer catastrophic losses in the process. Yuichi Kayama, the Moon Division’s captain, leads a daring rescue operation to liberate Yoneda and, with the help of the Imperial Japanese Navy, destroys the Japhkiel incubation facilities. Kayama attempts to arrest Furlong, but the latter escapes aboard a Japhkiel, merging with the surviving Japhkiels to overpower the Flower Division and shatter Ratchet’s Eisenkleid.
The climactic turnaround arrives when Ichiro Ogami arrives from Paris in a F2 Koubu to join the Flower Division in a final stand against Furlong and the Japhkiels. Yoneda, emboldened by the turn of events, orders the arrest of Tanuma, while Maria uses a bullet infused with spirit energy to end Hamilton’s threat once and for all. The immediate danger subsides, and the Flower Division—now tempered by defeat and resolve—looks toward healing and renewal.
In the recovery that follows, the Flower Division and Ratchet stage a musical performance inspired by Kyōka Izumi’s The Sea God’s Villa. Through the production, Ratchet lays bare her anxieties about the collapse of the Star Division and seeks forgiveness from Sakura, who offers guidance and understanding. The improvisations and emotional honesty shared during the performance help the group find a path forward. Despite the deviations from the script and the scars left by recent battles, the play becomes a resounding success, symbolizing resilience, reconciliation, and a renewed sense of purpose for Tokyo’s defenders and performers alike.
