In the year 1633, Japan is closed to all foreigners. Mixed-race children are treated as demons, monsters, less than human. Some years later, Mizu, a young samurai with blue eyes, enters a noodle shop. When Hachiman the Flesh-Trader threatens the shop owner's son Ringo at gunpoint, Mizu cuts off several of his fingers and demands to know where he got his gun. Having been told that it was from Heiji Shindo, the samurai sets off again into the winter cold. Ringo follows suit and begs to be made an apprentice but is soundly rebuffed.
In flashbacks, a young Mizu is chased to a cliff by a pack of boys, one of whom jeers, "Your whore mother killed herself because your father is a white devil!" Suddenly a blue comet arrives, scaring off the children. Mizu watches as a blind old man struggles to lift the meteorite and then helps him load it into the cart. The man turns out to be Master Eiji, a renowned swordsmith, and he takes Mizu on as his apprentice.
Once in Kyoto, Mizu locks eyes with a noblewoman in a litter: Akemi. She meets with her father, Lord Tokunobu, and convinces him to marry her to an undefeated swordsman with humble beginnings, Taigen, whom she has a secret relationship with.
At the Shindo Dojo, Mizu asks politely but insistently to deliver a message to the master of the dojo. Once rebuffed enough times, Mizu cuts through the students with ease, using only a wooden sword, until Taigen, the best swordsman in the dojo, challenges the interloper to a duel. They recognize each other from childhood: Taigen was one of Mizu's bullies. He wins but declines to administer the killing blow, opting to mock Mizu instead for being mixed-race. Enraged, Mizu takes off the wrist and ankle weights, defeats Taigen, and slices off his topknot, dishonoring him.
The master intervenes and reveals that Heiji Shindo is on Tanabe Island guarding the white man that Mizu has sworn to kill. Mizu leaves Kyoto and bathes in a waterfall, revealing that she is a woman.
Tropes for this episode include:
- Asshole Victim: Hachiman buys the daughters of poor families and forces them into prostitution, so the audience won't be bothered when our heroine cuts his fingers off.
- Awesomeness by Analysis:
- Despite being blind, Swordfather is able to tell how a samurai uses his sword by placing his hand on their back and feeling the movement of their muscle. Mizu in turn is able to master the technique by watching them do the same.
- When Taigen and Mizu are facing off in the snow, they're shown running through each other's opening move in their heads and adjusting their position accordingly.
- Badass Boast: When Hachiman asks if Mizu wants to fight his gun with a sword, she responds, "You don't deserve my blade. You don't even deserve this blade."
- She has a few more at the Shindo dojo:Shindo-Ryu fighter: Put down that toy and draw your sword!Mizu: (puzzled) But...then you'll die.
- And also:Taigen: Who dares challenge the Shindo dojo?Mizu: Well, no one at this dojo has offered much of a ch—[gets smacked across the face with a wooden sword]
- She has a few more at the Shindo dojo:
- Blind and the Beast: Mizu feels guilty about receiving the blind Swordfather's hospitality and tutelage, and blurts out the truth about her mixed blood, but he refuses to send her away. Before departing as an adult, Mizu also tries to tell him that she's a Sweet Polly Oliver but Swordfather cuts her off, implying that he's either guessed the truth or simply doesn't want to know anything that might affect how he regards his apprentice.
- Brick Joke: While schooling the virgin Ringo in lovemaking, the prostitutes tell him that breasts are like peaches. At the end of the episode Ringo catches Mizu Skinny Dipping and can only say, "Peaches..."
- Bullying a Dragon: Incidents of individuals hurling verbal abuse at Mizu after learning firsthand how fearsome she is serve as near-Bookends. Taigen has the excuse of recalling Mizu as both the Street Urchin the kids in his home village used to kick around and the fighter he fought on what he thought was equal terms moments ago to explain his failure to internalize how dangerous antagonizing the 'dog' in question was, but all Hachiman knew was that the 'dead-eyed half-breed' just effortlessly maimed his hand and wrecked his gun with a kitchen knife rather than bothering with the openly worn sword.
- Combat Pragmatist: During her duel with Taigen, Mizu dashes snow into the air with her sword to throw him off. It works for a moment.
- Commonality Connection: Lord Daichi is Nouveau Riche and is considering marrying his daughter to a nobleman who will add to the family's wealth and status, but Akemi and Seki convince him to accept Taigen instead, whose rise to greatness from a lowly position, solely due to his skill as a samurai, is similar to Daichi's own rise to lord from the mere son of a pig farmer.
- The Determinator: Ringo wants to be Mizu's apprentice and neither being tied to a tree, threatened with death, or even three days in a whorehouse is enough to stop him tracking her down.
- Even the Girls Want Her: Mizu has a slight Jaw Drop on seeing the beautiful princess Akemi pass by.
- Establishing Character Moment: Mizu's confrontation with Hachiman shows off her fortitude, intelligence and deadly skill. She is completely unfazed by the gun, instead analyzing its make, proving her to be surprisingly knowledgeable with Nerves of Steel. When he gets violent, she cuts off two of his fingertips using a nearby kitchen knife without breaking a sweat.
- Eye Scream: One of the Shindo-Ryu pupils gets one of these, courtesy of some quick swordplay from Mizu—and one of his classmate's teeth.
- Foreshadowing: The sound that Mizu's sword makes is the same sound the meteorite made whenever it was struck. This is the first clue that the sword was made from the meteorite.
- Fingore: Mizu slices off several of Hachiman's fingertips after he points his gun at her. And a couple more after he insults her.
- Gender Reveal: While it may not be much of a reveal to the audience, since Mizu's gender is explicitly stated in the premise and some of the episode descriptions (and is voiced by a woman, albeit a deep-voiced one), Ringo stumbling across Mizu bathing at the end of the episode definitely counts.
- Guns vs. Swords: Hachiman makes the mistake of not putting some distance between himself and Mizu, negating the advantage of his pistol.
- Half-Breed Discrimination: Part of the Deliberate Values Dissonance of the setting, explained from the first few frames. Mizu's blue eyes give her away as half-white; people cower or call her a demon/dog as soon as they find out, so she wears a wide-brimmed hat and tinted glasses to hide.
- Hear Me the Money: Swordfather raps the meteorite with his tongs; hearing the ring of Thunderbolt Iron he muses that "the heavens throw treasure."
- Hard Work Hardly Works: Averted. After discovering Mizu making a kitchen knife, Swordfather tells her to make a thousand more, and then she might be ready to start on swords. By the time Mizu leaves she's Surpassed the Teacher, having forged the Thunderbolt Iron that Swordfather was unable to melt down into her own sword.
- I Am Not Left-Handed: Taigen had just won two (frankly rather close) fights with Mizu, one with bokken and one with live steel, before leaving his old "playmate" bleeding in the snow. Then four sets of weights hit the ground, and seconds later so does he.
- Ineffectual Death Threat: Three members of the Shindo school are glad when Mizu refuses to leave, because now they have an excuse to kill her. Smash Cut to all three being tossed through the shōji by Mizu, who isn't even holding a weapon.
- Imposed Handicap Training: Mizu has been wearing weights around her ankles and wrists from a young age, as seen in a flashback. Removing them gives her a Heroic Second Wind to beat Taigen.
- Pet the Dog:
- Mizu is shown praying for aid in her quest for vengeance, but then she smiles and also asks that Swordfather be protected "from time and harm."
- Upon leaving Kyoto, Mizu throws the hair comb that she got from cutting off Taigen's topknot to the mother and girl huddled outside the gates, so that they sell it or bribe the guards to let them in.
- Pre-emptive Declaration: "You don't deserve my blade. You don't even deserve this blade."
- Rewatch Bonus:
- Mizu only reacts to Hachiman's nastiness when he calls Ringo a dog; it's revealed later in the episode that Mizu has been called that all her life.
- The kitchen knife Mizu uses to cut off Hachiman's fingertips is one of the kitchen knives she made as an apprentice, as shown by her sigil engraved on the blade. That explains the "You don't even deserve this blade" remark.
- Snow Means Death: Subverted; Mizu is introduced walking through the snow before meeting Hachiman, and when Taigen is told by his dojo master to kill Mizu, it cuts to them facing each other outside in the snow. But in neither case does she actually kill anyone.
- Strange Minds Think Alike: Both Mizu and Heiji Shindo say to the master of the Shindo dojo, "Your students need better training."
- Training Montage: Mizu, to Tomoyasu Hotei's theme from Battles Without Honor and Humanity no less!
- Traumatic Haircut: Mizu cuts off Taigen's topknot after he insults her about her ethnicity, leaving him with a large bald patch. Afterward, his fellow trainees turn away from him, since honor is stored in the topknot.
- Water Wake-up: Mizu rubs snow on her face to revive herself after Taigen knocks her down.
- Who Dares?: Mizu cops a lot of this from the students and teachers at the Shindo dojo. Unfortunately for them, she does.
- Would Hurt a Child:
- Young Mizu gets beaten up by the other village boys lead by Taigen, who it's implied was going to kill her before the meteorite impact scares him off.
- Swordfather gives young Mizu a rap with his tongs whenever she messes up. However he always explains what she did wrong and it teaches her the precision needed for his craft. In one scene he goes to hit her but she immediately corrects the mistake, so he doesn't.
- Your Cheating Heart: Taigen is celebrating his impending nuptials with sake and prostitutes, until Mizu interrupts the celebration.
