A gutsy crew of Joseon pirates and bandits battle stormy waters, puzzling clues and militant rivals in search of royal gold lost at sea.

At the cusp of the founding of Joseon Dynasty, an envoy from China is delivering Emperor’s Ming’s Royal Seal. But nature in the form of a giant whale intervenes and swallows the royal seal. When a generous reward is offered to whomever can retrieve the royal seal from the belly of the whale, the race is on. A group of mountain bandits led by Jang Sa Jung and a group of pirates led by Yeo Wol go after the lost treasure, but who will get to to it first?