Grown up son arrives home to learn his father, the newly elected mayor, has been assassinated. So he journeys down a path to find the assassin and gets involved with two opposing yakuza gangs.

The Blue Pearl depicts the interplay between a young man from Tokyo and two ama (pearl divers; literally “women of the sea”) in a superstitious coastal town. Though raised within the same tradition-bound crucible, the two women – Noe and Riu – are portrayed as diametric opposites; the former meek but affectionate, the latter strong-willed but jaded by a tryst with metropolitan life.

Gang of robbers quarrel about the loot, but when one of them gets killed, his younger brother seeks them out to ice them one by one.

In June 1941, Captain Kagawa (Ryutaro Tatsumi), who had just graduated from the military academy, was assigned as the captain of a sentry patrol in Beiman, which was located on the opposite side of the Heilongjiang River from the Semidomka region of the Soviet Union. His predecessor, Lieutenant Kishi (Kawamura Kenichiro), a mild-mannered middle-aged man, had earned the trust of his men and the villagers by relaxing his military duties. However, newly appointed Lieutenant Kagawa thinks that Kishi's way of doing things is sloppy and begins to train the soldiers furiously in order to teach them a lesson.