The Satomi clan of Awa is thrown into crisis when the shogun’s heir, Takenari, takes a liking to their heirloom, eight crystal beads known as the Fusehime no Tama. Forced to promise them as a gift, the Satomi fall into a trap: the scheming councilor Hōjō Sado-no-kami orders Hattori Hanzō’s Iga female ninja to swap the genuine beads with convincing fakes. Cornered, the Satomi’s elder retainers, the eight dog-warrior descendants, commit ritual suicide and charge their successors, currently training in Kōga ninjutsu, with retrieving the real beads. But those successors have long since abandoned their harsh training and fled to Edo, where they have become idle street performers, beggars, gang leaders, and thieves. They have no interest in heeding their fathers’ dying wish.

Everything changes when Murasame, the young wife of the Satomi lord Tadayoshi, blames herself for the crisis and secretly leaves the castle to act. One by one, the eight degenerate men are drawn to her; the first, Inuta Kobungo, a lazy giant living as a beggar, volunteers to help. He storms Hattori’s mansion alone, challenging the Iga kunoichi openly. Kobungo is killed, but his direct challenge forces the Iga to keep the beads intact out of pride. His death ignites the others. Each of the eight dog warriors, harboring a secret adoration for Murasame, sets out to reclaim one of the eight beads, employing bizarre and deadly ninpō techniques. The battles take place in brothels, theaters, and the streets of Edo, with the dog warriors facing the eight Iga kunoichi — a leader named Funamushi, the seductress Asagao, the shrewd Samo, and others — each skilled in their own lethal arts.

As the warriors fight and fall, they recover beads one by one. Dogū Kakutaro uses the forbidden Flesh-Carving Technique to reshape fellow warrior Inuzuka Shino into a perfect replica of Murasame. Shino, who has always worn women’s clothes and performs as an acrobat, becomes the decoy while Dogawa Sōsuke rescues the real Murasame from captivity. Kakutaro later carves his own face to impersonate the Iga commander and retrieves a bead at the cost of his life. The strongest warrior, Inue Shinbei, launches a final assault on the mansion, buying time for the others. One by one, only Shino remains alive. At the end, as Murasame is escorted to the shogun’s castle to present the recovered beads, Shino slips the last real bead into her kimono from the shadows. He vanishes into the spring streets, the sole survivor of the desperate mission, while Murasame successfully offers the genuine beads to the shogun’s heir, saving the Satomi clan from ruin.