Ami Hyūga Minase Yashiro is an average high school girl whose ordinary days crash into tragedy when her brother Yu Hyūga [Ryôsuke Kawamura] and his friend are killed by bullies led by Sho Kimura [Nobuhiro Nishihara]. As Ami searches for answers, she discovers that the bullies are tied to a ninja-yakuza clan, a revelation that drags her into a dangerous hunt for justice. The pursuit is relentless, and the clan proves to be merciless, overpowering Ami and severing her left arm in a brutal confrontation. Yet her resolve stays intact; she escapes and seeks shelter with Takeshi’s parents, Suguru Sugihara [Yuya Ishikawa] and Miki Sugihara [Asami], two warmhearted mechanics who stand by her side. They retrofit her with a frighteningly capable prosthesis: a multi-barrelled machine gun that amplifies her thirst for revenge.
With new tools and a fiercer sense of purpose, Ami and Miki press on, dismantling the clan piece by piece. The quest for vengeance, however, sparks a chain reaction: the families of the victims unite, driven by grief and anger, and begin to exact their own forms of retribution. The film widens its lens to show how personal loss spirals into a broader battlefield, where loyalty, power, and fear collide.
The showdown reaches the heart of the yakuza’s hideout, and the violence intensifies. During the brutal clashes, Miki loses her right foot and ultimately dies, a crushing blow that deepens Ami’s resolve even as her own body weakens. In a pivotal moment, Ami’s machine gun is taken from her during a fierce exchange with Sho’s father Ryûji Kimura [Kentaro Shimazu], forcing her to adapt and rely on Miki’s remaining tool: a chainsaw. The momentum shifts as Sho clings to hostages to deter Ami, while his mother, Violet Kimura [Honoka], attempts to incapacitate her with a drill-based weapon.
A tense sequence unfolds when a hostage’s wet fate creates a chaotic distraction. Seizing the moment, Ami trips Violet onto a urine-soaked surface, delivering a decisive electric shock that eliminates one of her fiercest opponents. The power balance tilts as Ami beheads Sho and Violet, a stark culmination of a trail of tragedy, blood, and raw determination.
With the immediate threat gone, Ami faces a painful void and contemplates an end to her own life. Just as she appears to be sliding into surrender, a new noise from behind her breaks the stillness. She turns, sword in hand, and the film leaves a charged, unresolved note—an open question about what comes next for a girl who survived so much, and what she will choose to live for now.
