Premise The story is set in the environs of
Mount Yōtei in
Ezo (modern-day
Hokkaido, Japan) in 1603, 329 years after the events of
Tsushima. The main character, Atsu (
Erika Ishii /
Fairouz Ai), is a wandering mercenary who adopts the persona of the vengeful
onryō in her quest to hunt down the "Yōtei Six" – renegade
samurai Lord Nariaki Saito (
Feodor Chin /
Miou Tanaka) and his lieutenants the Snake/Yukiharu (
Nelson Lee / Mutsumi Sasaki), the Oni/Lord Hyozo (Tommy Kang /
Atsushi Miyauchi), the Kitsune/Dojun (
Matthew Yang King /
Jun Fukuyama), and Saito's sons, the Spider/Sakichi (
Robert Wu /
Tomokazu Sugita) and the Dragon/Ukichi (
David Sakurai /
Tomokazu Seki) – who, sixteen years prior, had slaughtered her family, destroyed her home, and left her for dead, pinned against a burning
ginkgo tree with her father's
katana. Supporting characters allied with Atsu – referred to as her "Wolf Pack" – include Oyuki (Jeannie Bolet /
Romi Park), a traveling
shamisen performer and former Yōtei Six member; Jubei (Noshir Dalal / Shogo Nakamura), Atsu's twin brother and a
Matsumae clan samurai who goes by the title Lord Kitamori; and Kiku (
Suzie Yeung /
Shion Wakayama), Jubei's teenage daughter.
Synopsis In 1587, after her family is killed, a young girl named Atsu is left for dead by a band of criminals known as the Yōtei Six, led by the renegade
samurai lord Nariaki Saito, in an event later called the Night of the Burning Tree. Atsu survives and flees
Ezo, becoming a wandering mercenary in the south for the next sixteen years before returning home to take her revenge against the Yōtei Six. She first finds the Snake drunk in a backwater village and kills him, but is mortally wounded in the process. Atsu miraculously survives and recovers from her wound, causing witnesses to fearfully dub her the "
onryō", while Saito puts a bounty on her head. Returning to her destroyed family home, Atsu begins her hunt for the remaining Yōtei Six. She learns that Saito is building a rebel army to claim the entire island of Ezo for himself as the self-appointed "Shogun of the North"; the
Matsumae clan, who are loyal to the
Shogun, have declared war against Saito. Atsu travels around Yōtei, killing Saito's forces, assisting locals, and training under various weapon masters. As Atsu's reputation grows, many
rōnin attempt to take her bounty, and Atsu gains a following dubbed the "Wolf Pack". After learning how to dual wield
katana from Hanbei, formerly Ezo's best bounty hunter and an old friend of her father, Atsu attempts to assassinate Saito at his training camp, but fails. Surprised she is alive, he challenges her to a duel, which is interrupted when the Matsumae attack the stronghold; Hanbei manages to save her and encourages her to stop chasing her vendetta, while Saito escapes into hiding. While pursuing the Oni in Ishikari Plain, Atsu discovers her brother Jubei also survived the massacre and was rescued by the Matsumae clan, rising in rank to become the samurai officer Lord Kitamori. Atsu and Jubei infiltrate the Oni’s stronghold, Ishikari Castle, to assassinate him, but their attempt is unsuccessful, and the two flee. Jubei struggles to reconcile his love for his sister due to his sense of duty to the Matsumae, coupled with her suicidal recklessness and disregard for the lives of the prisoners taken by the Oni, and he leaves her behind in frustration before returning to his men. Atsu heads to a Matsumae camp to obtain information from a former Oni Raider named Mad Goro, but the Oni's forces arrive and slaughter the samurai. The siblings reconcile and learn of a secret passage into the castle. They infiltrate, incite a prisoner rebellion, and slay the Oni together, and Atsu helps burn down the castle. After narrowly surviving an ambush in Teshio Ridge, Atsu assists the traveling
shamisen performer Oyuki to track down the Kitsune and thwart his production of
wolfsbane poison at his fortress. When the Kitsune fails to recognize her, Atsu deduces that Oyuki was the original Kitsune; Oyuki admits she was formerly the Kitsune who served as Saito's
shinobi, who saved Atsu and let her escape after Saito hanged Atsu's mother. Disillusioned by the Night of the Burning Tree, Oyuki planned to betray him, but was herself betrayed and replaced as the Kitsune by her disciple, Dojun, with Saito branding her as punishment. After a duel, Atsu forgives Oyuki, who teaches her
shinobi techniques, gives her the antidote to Dojun's toxin, and helps her to kill him. As Atsu and Jubei reunite at home, Jubei meets Oyuki and nearly attacks her in anger when she reveals she was the Kitsune, before she informs the siblings that Saito and his sons, the Dragon and the Spider, are planning to attack the
Matsumae heartland, shocked to discover that Saito has an entire fleet of warships. After breaking through enemy lines, Jubei saves a teenager from execution, revealing she is his daughter, Kiku. While Jubei takes her to the safety of
Matsumae Castle, Atsu and Oyuki search for Saito's sons. With the Dragon proving too cautious after Atsu and Jubei attempt to kill him at the lighthouse, Atsu captures his younger brother, the Spider, as he re-enacts the Night of the Burning Tree as a play; enraged, she massacres the Saito forces, but stops at killing the Spider, and Oyuki takes him to Matsumae Castle. The Matsumae organize his public execution to lure out the Dragon, with the Spider mentioning his clan's burial grounds in Tokachi Range, but they are outmaneuvered by a Saito counterattack on the castle and distracted by Saito's ships. Jubei and Oyuki leave to defend the castle and save Kiku, imploring Atsu to help, but she stays to kill the Dragon; as the castle is destroyed, Jubei and Oyuki end up missing, despite Atsu fighting through Saito's men to reach them. After killing his way through the samurai to escape, the Spider recovers the Dragon's body, but Saito disowns him in frustration as punishment for letting his brother die. Finding Kiku safe at a nearby temple, Atsu evacuates her to her family home and begins to have doubts about her grudge when Kiku similarly becomes obsessed with revenge and lambasts her for abandoning Jubei and Oyuki to kill the Dragon, going to Hanbei for help. At Saito's clan cemetery, she tracks down the Spider, who reveals Jubei and Oyuki were captured by Saito, and tells her that he lost his infant sister after Atsu's father betrayed Saito. Following a duel that leads Atsu to spare the Spider, he offers to lead her to his father's castle, before leaving Ezo for the mainland. Atsu rescues Jubei and Oyuki and learns Saito is waiting for her at her family home with Kiku as his hostage. Together, Atsu and Jubei duel Saito, but Jubei is fatally wounded. Atsu manages to disarm Saito and pin him to her family ginkgo tree with both of their swords, and when he begs her to kill him, she leaves him to bleed out, promising to Jubei that she will raise Kiku in his stead before Jubei dies of his wounds; when Atsu sees Kiku as her younger self, she embraces her as they mourn Jubei's death. Having finally found closure and something to live for instead of revenge, she retires the
onryō role to live a quiet, peaceful life as Kiku's guardian. == Development ==