Yojimbo, a ronin, (Mifune) is secretly commissioned to travel to Sanshu Pass. This once crucial thoroughfare in the time of the warlords is now just a backroad used by outcasts. There he is to wait, until an undisclosed event occurs.

On his journey, he rescues a woman from her violent husband, and takes her away with him. They arrive at an inn, run by an old man and his granddaughter. This place has become home to a bunch of misfits, including a one-time physician (Katsu), a wandering gambler, and an officer of the law together with his prisoner. A dramatic chain of events unfolds, forcing the once hostile and untrusting characters to unite in a common cause: their own survival.

Ambush At Blood Pass examines the complex nature of the human condition under pressure.