Two parallel storylines eventually converge as we follow a 14th century hero and heroine who become treasure-hunting rivals and, inevitably, partners and lovers. Jang Sa-jung (Kim Nam-gil) is an army officer who doesn't go along when his general supports a coup d'etat. Jang fights his way out of immediate peril to become a forest bandit, the Crazy Tiger, complete with a comedy-relief monk with a big appetite. Yeo-wol (Son Ye-jin) is a pirate princess who leads an uprising against her mentor Captain Soma (Lee Geung-young) when he conspires with officials to save his own ass by selling out loyal crewmates.
The bad guys (above) and the good guys (below)
The coup being successful, the new regime receives legitimacy from "Ming," aka China. Legitimacy comes with a new country name, Joeson, and a new royal seal. The latter gets lost at sea and swallowed by a whale. The new ruler offers a huge reward for the recovery of the great seal, attracting both pirate Yeo-wol and bandit Crazy Tiger to the treasure hunt. Crazy Tiger is a total lubber but he has the expertise of ex-pirate Cheol-bong (Yoo Hae-jin), who quit Soma's crew due to chronic seasickness but often falls landsick as well. He proves helpful to the bandits even though he has a hard time making them understand just how big a whale is. Yeo-wol has a competitive advantage not just because she's a pirate but because she has an affinity with whales going back to her childhood. But she finds herself fighting with Crazy Tiger over equipment, most importantly over imported European explosives. Meanwhile -- wouldn't you know? -- the vengeful Soma and Crazy Tiger's old commander have joined forces to catch the whale and take the treasure for themselves.
That's the framework for some oldschool swashbuckling with a wuxia edge as well as FX setpieces more reminiscent of the Caribbean movies. The main such event comes fairly early: an urban chase scene with Yeo-wol pursuing Crazy Tiger, using an aqueduct as a flume ride until Tiger wrecks it with an antique rocket, setting an attached giant water wheel rolling through town, in and out of the heroes' path. I'm not sure of the physical logic of the wheel's wanderings but it's an amusing spectacle. There's good comic chemistry between the leads, too, who go through a lot of adventure tropes together, from Defiant Ones style shackling to mutual seduction through boastful comparison of battle scars. The comic relief is solid throughout, especially the award-winning Yoo Hae-jin as the cantankerous misfit who bridges the pirate-bandit divide, but the monk is cool as well. There's also some presumably veiled political satire, with the usurping Joeson regime an analogue for North Korea, though the usurper is offered redemption with advice to shun the influence of Ming that seems directed at modern China. For foreigners, the film doesn't suffer if you don't get any of that. The spirit of high adventure that prevails translates pretty well into any language.