The mercenary sea

1938 -- the South Seas: Japan has invaded China. War in Europe is imminent. The world hasn't been entirely mapped yet, and adventure is just over the horizon. Ex-bootlegger Jack Harper captains the Venture, a refitted WWI German U-Boat, with a crew of expats, mercenaries and fortune hunters. They do whatever it takes to stay afloat, running up against pirates, headhunters and other enemies. Meanwhile, Jack dreams of landing the greatest score of his life: finding the legendary lost island of Koji Ra, home to fantastic beasts, and even more fantastic treasure.