In The Last of the Sea Women, an unusual group of warrior grandmothers wage a spirited battle against vast oceanic threats. The Hanyo divers from Jeju Island in South Korea, who are often referred to as real mermaids, have been known for centuries to dive to the bottom of the ocean (without oxygen) to collect shellfish for sustenance. Today, when most Hanyo are in their 60s, 70s, and 80s, their traditions and way of life are in immediate danger. But these fierce, cheerful, hardworking women refuse to give in even an inch, which is facilitated by the struggle of the younger generation to revive the way of life of their ancestors through social networks. Exploring what drives young and old, this touching documentary focuses on their close friendship, intelligent independence and infectious sense of empowerment. It becomes an inspiring story about women who challenge world powers to protect their beloved ocean and inspire a new generation.