About 1786 the doings of a demented lord results in many masterless samurai, including Iyemon (Kei Sato) who is used to luxury and cannot adjust to the hand-to-mouth conditions & piecework of umbrella making. Having hired ruffians to make him look like a superior swordsman, he arranges for himself the opportunity of a profitable marriage. He hires the half-blind masseur Takuetsu (Sawamura Sounosuke) to seduce or rape his wife (Kyoko Mikage), so that she can be divorced or killed for adultery. But the masseur takes pity & informs Oiwa of her husband's horrid plot. Assisted by the merchant's daughter he intends to marry, Iyemon disfigures his wife attempting to poison her so he can marry higher. There's a lovingly gruesome sequence as she combs blad patches into her hair, kneeling deformed at her mirror, weeping with bitterness. She eventually cuts her own throat, swearing revenge.

A young female samurai comes upon a dying messenger and agrees to deliver the scroll he was carrying to its destination. However, unbeknownst to her, the scroll is actually a formula for a new kind of gunpowder. An evil clan that is planning to overthrow the Emperor is also after the scroll, and they try to take it from her.