In 1801, following a new king's ascent, scholar CHUNG Yak-jeon, who once served the late king, faces exile to Heuk-san Island. Expecting fear, he discovers astonishment in the island's diverse sea creatures. He encounters Chang-dae, a young fisherman deeply devoted to Confucianism and possessing vast sea knowledge. Captivated, CHUNG plans a sea-themed book and proposes a deal: Chang-dae aids the book in exchange for assistance with his Confucian studies.