Ryoo Seung-wan returns with a strong female-led aquatic crime-action epic. In 1970s South Korea, women free divers who have harvested shellfish suffer a threat to their livelihoods after a chemical factory opens in their seaside village. Using their specialty in diving and knowledge of the waters, old friends Choon-ja and Jin-sook start to smuggle goods. However, when they find out they are being set up, they plan for the most mind-bending and dangerous job to seek revenge, which could become their biggest break—or the end of it all.