In the late 19th century, a disillusioned Civil War veteran is haunted by his past and drowns his trauma in alcohol. Searching for purpose, he accepts a job in Japan to train the Emperor's conscript army in the use of modern firearms and tactics. His task is to suppress a rebellion of the traditionalist Samurai, who remain devoted to their ancient ways and the art of the sword. Soon after his arrival, the inadequately trained army is rushed into a premature battle against the highly skilled Samurai warriors, resulting in a crushing defeat for which he bears great responsibility.

Captured by the Samurai, the veteran finds himself a prisoner in a remote village. As time passes, he becomes immersed in his captors' way of life, gaining insight into their honor-bound culture and the reasons behind their opposition to the Emperor's westernizing policies. His initial contempt for the Samurai gradually gives way to respect, and he is particularly drawn to the Samurai leader, whose strength and wisdom challenge his preconceived notions. The veteran's loyalties become conflicted as he's compelled to face the stark contrast between the Japan he's been contracted to build and the one he's come to understand through the eyes of the Samurai.