In the sixth year of King Aejang's reign, Gung Bok, a slave at the Cheonghae shipyard, dreams of freedom beyond the sea. His failed escape to Tang China brings brutal punishment, but that doesn't stop him. Determined to defy his fate, he begins building the strength to fight back. After clashing with Chang Gyeom, the proud son of an official, he secretly trains in swordsmanship under Yeom Jang, a pirate concealing his true identity. When his father is killed and he's framed for the crime, Gung Bok falls into despair, until a chance encounter with a master swordsman reignites his will to fight. Forged through hardship and sharpened by loss, Gung Bok rises as a skilled warrior. Now, with the vast sea as his stage, he must face both his past and his destiny.