We now have a somewhat clearer picture of what that means thanks to a new trailer for the DLC. This is the first part of two planned add ons where you'll play as Juli Kidman, partner of the main game's Sebastian.
The DLC will hit on March 10th in the US and March 11th in Europe. The second part, The Consequence has not yet been dated. There will also be a third DLC called The Keeper, but little is known about that yet.