In ancient Kyoto, Japan during the Edo period a wealthy samurai man, Job-san (Ken Watanabe), dedicates himself to his family and his home. Generally samurai are soldiers who serve a feudal Lord, but Job-san is a different kind of samurai because he only serves the Lord God with absolute loyalty. During the film, God and Satan (both Seizo Fukumoto) converse about Job-san's loyalty. Satan attempts to persuade God into thinking that Job-san is only loyal because his life is full of wealth and provisions.
This conversation begins a test of the loyalty for Job-san through a series of terrible events that occur to him and his family. The unfortunate events eventually leave Job-san distraught and alone. His only friends fight with him, telling him that he must have done something wrong to anger to God. Job-san must defend his loyalty and honor.