After her husband suddenly disappears, leaving behind debts, Yuko has no choice but to seek help from her only remaining relative—her brother-in-law—and moves to a remote seaside house. But he refuses to provide her with even a place to sleep or food to eat. With no other options, Yuko resolves to become an ama, a female diver, to support herself. Enduring the harsh conditions of the sea, she overcomes countless hardships and gradually masters the skills needed to harvest seafood. One day, while diving deep underwater, Yuko discovers an extremely rare pearl. This precious find at the bottom of the ocean becomes the turning point that will drastically change her life.