While Black Flag followed the swashbuckling exploits of pirate captain Edward Kenway, the DLC explores the story of his first mate, Adewale. An escaped slave, the plot finds him shipwrecked in San Domingue, and concerns his quest to acquire a ship and crew of his own so he can free the other slaves he left behind. It is, as you might expect, a rather more serious but no less brilliant tale than that of Black Flag.
The DLC will be available for download as a game in its own right from February 19 for PC, PlayStation 3 and PlayStation 4. Ubisoft hasn't mentioned the game coming to Wii U or Xbox.