Ključna riječ Kunoichi

Casey (Scott Adkins) živi u Japanu i uči borilačku vještinu ninjitsu. Miljenik je učitelja, koji mu podari vrijednu ninjinu opremu – odjeću i oružje. No jedan drugi učenik, Masazuka (Tsuyoshi Ihara), smatra da on zaslužuje ninjin oklop i napadne Caseya. Protjeran iz grupe, Masazuka se priključuje kriminalcima koji se nazivaju The Ring te postaje ubojica. Učitelj govori Caseyu da ninjin oklop ponese u Ameriku kako ga se Masazuka ne bi dočepao. Ubrzo, Masazuka ubija učitelja i kreće put Amerike pronaći Caseya.

In order to protect an ordinary businessman, Tsukasa Atsumi, from demons, a genius kunoichi, Shizuri Ideura, signs a master-servant contract with him on the condition that she stays with him. Despite her cool appearance of defeating demons, Shizuri is an otaku NEET who spends all her time playing video games. While Shizuri is spoiled by Tsukasa and leads a lazy cohabitation life, the quirky Kunoichi gather together.

A naive ninja ran away from her remote village and meets a high school girl assassin! The start of an unpredictable life together between ninja x assassin.