During the reign of 5th Shogun Tokugawa Tsuneyoshi a troupe of Chinese acrobats travel to Japan to help celebrate the building of the Yushima Shrine. At the same time a series of mysterious assassinations take place with a strange and unknown weapon. Master swordsman Saotome Mondonosuke, a 'Hatamoto' (direct retainer of the Shogun) and a man who loves action takes it upon himself to get to the bottom of the mystery and and solve the puzzling crimes.