During the tumultuous period marking the establishment of the Joseon Dynasty, a Chinese envoy is set to deliver the Emperor's Ming Royal Seal when a colossal whale disrupts the journey by swallowing the precious item. With a lucrative reward promised for its recovery, mountain bandits led by Jang Sa Jung and a crew of pirates under Yeo Wol plunge into a fierce competition to reclaim the lost treasure. As both groups navigate treacherous waters and face unexpected challenges, the race intensifies, revealing alliances and rivalries in their desperate quest for fortune.