Aging samurai Hanshiro Tsugumo arrives at the home of Kageyu Saito and asks to commit a ritual suicide on the property, which Saito thinks is a ploy to gain pity and a job. Saito tells Tsugumo of another samurai, Motome Chijiiwa, who threatened suicide as a stratagem, only to be forced to follow through on the task. When Tsugumo reveals that Chijiiwa was his son-in-law, the disclosure sets off a fierce conflict.

Rick, a down-and-out American boxer, is hired to transport a sword to Japan, unaware that the whole thing is a set up in a bitter blood-feud between two brothers, one who follows the traditional path of the samurai and the other a businessman. At the behest of the businessman, Rick undertakes samurai training from the other brother, but joins his cause. He also becomes romantically involved with the samurai’s daughter.