Korea in 1388. When his general Yi Seong-gye refuses to attack Chinese troops, the soldier Sa-jung sees this as high treason and challenges his commander to fight. After a duel with his former master Hong-gab, he has to flee and becomes the bandit "crazy tiger". However, the general overthrew the government and founded the Joseon dynasty as the new king.
A few years later, the pirate Yeo-wol leads a mutiny against her captain So-ma when he wants to hand over some of his people in order to continue to have a free hand in return. In the meantime, a delegation to the Ming emperor in return for tribute payments and the transfer of 300 children has succeeded in getting the new king recognized. A seal is given to him as a sign of his rulership. On the way back, the emissary's ship attacks a gray whale cow with her young. She sinks the ship and swallows the seal.
Since that would be seen as a bad omen, the true facts are withheld from the king and the loss of the seal is blamed on pirates. In order not to atone for something she did not do, Yeo-wol agrees, against her conviction, to take part in the whale hunt. So-ma, who survived the mutiny, also goes whaling alongside the Navy. The third party is the rather unsuccessful bandit "Crazy Tiger" and his band of robbers, who first have to be introduced to nautical basics by a former pirate (do not breathe under water!), But are quite innovative as lateral entrants (you increase the speed of the boat if you let yourself be pulled by a great white shark).