In 1801, after a new king ascended the throne, a scholar Jeong Yak-jeon who served the late king is exiled to Heuk San Island. When he lands on the unknown island with fears, rather he is amazed by wonders of various sea creatures. There he meets Chang-dae, a young fisherman who is a huge admirer of Confucianism and has a wide knowledge about the sea. Fascinated by his knowledge, Jeong decides to write a book about the sea and asks Chang-dae to help him write the book, in exchange for helping Chang-dae’s study of Confucianism.