The extraordinary lives of Jeju Island’s female free divers are brought to the surface by one of South Korea’s biggest television personalities – Song Ji-hyo. The television star undertakes her greatest challenge yet – free diving with the legendary Haenyeo. Now mostly in their 80s, they risk their lives plunging up to 20 metres to the seafloor without air apparatus to gather shellfish. Most Haenyeo start training aged eight. Ji-hyo crams over 30 years of preparation into a month. As she tests her limits, Ji-hyo discovers how the changing marine environment coupled with an ageing population threatens the nation’s incredible Haenyeo heritage – and explores what it will take to preserve their way of life.