A young ballet dancer (Faye Viviana) killed with a throwing dagger in the wrong part of town near an abandoned cookie factory leads Castle (Nathan Fillion) and Beckett (Stana Katic) on an unusual case involving ninjas, mysterious phone calls, an underground Japanese club, a Yakuza financier (Ron Yuan) and geisha girls. And the further the group looks into the victim’s past the more mysterious her life (and death) becomes.
Not buying Castle’s ninja theory, Beckett takes a hard look at a rival ballet dancer (Mike Moh), but after her fiance runs into a pair of rival ninja while hitting up a geisha club with Ryan (Seamus Dever) and Esposito (Jon Huertas) where the victim was working at part-time she can no longer discount his outrageous theory. But she can be angry about Castle making out with one of the geisha girls (Arden Cho) for information.
The discovery of their victim’s past, the murder of her entire family by a Yakuza assassin known as “The Green Dragon” during her childhood, and the sister who is alive as well and impersonating a consulate officer (Brittany Ishibashi), leads to even more questions but also finally reveals the truth behind the ninjas and the reason for the young woman’s lifelong search for vengeance that led to her murder.
“The Way of the Ninja” proves (as anyone who was alive in the 1980s already knows) that adding ninja makes everything more awesome. Castle’s lines about the first ninja attack that Beckett can’t bring herself to believe are some of the best moments of the season. The B-story concerning Beckett fretting about an old rival doesn’t work as well, but the conversation about the pair making a concerted effort to remaining “not boring” is a nice touch (as is the cheap, but effective, final joke of the night involving Castle’s shiny new shuriken and Beckett’s boss).