The Nami family lives in a quiet fishing village at the tip of the Shima Peninsula overlooking Ago Bay. The family of four consists of her grandmother, Tom, who is in her sixties, her mother, Kura, and older sister, Saki, all women. Toma, despite her advanced age, is still the best diver in the village, Nami has grown up to be an excellent diver too. However, her older sister Saki was born with a mental disorder and no one in the village wants to do business with her. Nami, on the other hand, is very popular among the boys of the village, she is healthy and beautiful. The fisherman Shosaku is crazy about Nami, and day and night he asks her on dates. However, Nami has a crush on her cousin Yuji, who works for the fishermen's union, and casually rejects Shosaku's advances.

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.