一撃必殺の技を武器に、鮮やかに敵を倒す女剣士アルカ。旅をするアルカの目的は、師匠ホンを殺されたことへの「掟による復讐」だ。
仇は、謎の力「濁気」を操る女、ジン・ヴァレル。ジンは感情を見せず冷酷無比に人の命を奪う魔物のような存在だが、アルカもまた暗殺集団「剱一族」の者として、感情を殺し「仕事」を完璧に遂行することに特化して育てられており、2人は似た者同士であった。
旅の中、3人の女傑と出会うアルカ。歌舞と武術の達人カレン、酒好きで銃マニアのハズキ、盗賊団の女頭領ロアナ。この3人と奇妙な縁で結ばれながら、行く先々で人々と出会い別れるうちに、ホンが遺した教えを思い出していくアルカ。
ホンは、ある運命を背負って生を受けたアルカに力の使い方を教える立場でありながら、同時にアルカに一族の掟から解放されて欲しいと願っていた。
徐々にホンの教えの意味を悟っていくアルカ。アルカの中で、何かが変わり始めていく。
Armed with her one-hit-kill technique, the skilled swordswoman Alka defeats her enemies with dazzling precision. Alka’s goal as she travels is to exact “revenge by the code” for her slain master, Hon.
Her target is Jin Valel, a woman who wields the mysterious power of “Murk”. Jin is a cold and ruthless being who takes lives without showing emotion, like a demon, but Alka, as a member of the assassination clan “the Clan of the Sword,” has also been raised to specialize in killing emotions and perfectly executing “jobs,” and the two are similar in that regard.
During her journey, Alka meets three remarkable women: Karen, a master of song and dance and martial arts; Hazuki, a sake-loving gun enthusiast; and Rowana, the female leader of a thieves’ guild. As she becomes intertwined with these three through strange fate, and as she meets and parts with people along the way, Alka gradually remembers the teachings that Hon left behind.
Hon was in the position of teaching Alka how to use her powers, as she was born with a certain fate on her shoulders, but at the same time, he wished for Alka to be freed from the clan’s code.
Alka gradually realizes the meaning behind Hon’s teachings, and something begins to change within her.