As master assassin Usui Yuen investigates a series of attacks made on the grand samurai clan, the Satsuma, he encounters survivor and clan member Kurima Raizo. Together, they unravel a conspiracy behind the murders, the true nature of which appears far grander than anyone first thought. As they get closer to the truth, will they come out alive to exact revenge?<br> <br> (Source: Crunchyroll)