Like his father and grandfather before him, Kino is a poor diver, gathering pearls from the gulf beds that once brought great wealth to the Kings of Spain and now provide Kino, Juana, and their infant son with meager subsistence. Then, on a day like any other, Kino emerges from the sea with a pearl as large as a sea gull's egg, as "perfect as the moon." With the pearl comes hope, the promise of comfort and of security....