It's set in Japan after the turn of the 20th century (presumably). The protagonist is a swordsman named Kaneno Suzunosuke who comes to Edo to avenge her father's death by the 'headless man'. There she meets a pair of street performers, the scarred, deafblind, and mute Tsuki and the diminutive Inuchiyo who acts as the former's interpreter. Suzu quickly discovers that despite Tsuki's disabilities, she's a fierce fighter.
The main antagonists are a group of criminals called the Tengu, who wear said mythical creature's face as masks.
Tropes in Tokugawa no Saru:
- Beauty Is Never Tarnished: Averted with Tsuki, she bears numerous scars all over her body and is given a new one early, on the side of her mouth.
- Bifauxnen: Halfway through the first chapter, it's revealed that Kaneno Suzunosuke is actually a woman.
- Boom, Headshot!: One client of Tsuki's almost rapes her when an armed mob come in guns blazing, he dies.
- Creepy Crossdresser: Toyed with. Yoshimura 'the headless man' is often seen in women's clothing, as a mirror image of the Bifauxnen Suzunosuke. He tries to justify killing Suzunosuke's father saying it was necessary to kill him to avoid him falling into enemy hands, generally Suzu has to accept working with him.
- Fanservice: There is frequent nudity, mostly from Tsuki.
- Full-Frontal Assault: Tsuki 'sees' better the less clothing she wears.
- Historical Domain Character: Razputin, complete with Historical Villain Upgrade.
- The Oldest Profession: Tsuki and Inuchiyo's street performances aren't enough to pay their bills, so the former (and thankfully not the latter) works as a prostitute as well.
- Public Domain Character: One of the antagonists is James Moriarty.
- Token Mini-Moe: Inuchiyo, a young girl who acts as Tsuki's interpreter.