The DLC adds a 4 player scenario, with a new House, the Arryn as well as the Baratheon, Lannister and Starks. It is set in the era of the eponym book. It also radically change the win condition though the addition of a scoring system and objective cards.
Each House will received secret objective cards to choose from as well as its own unique House objective card. The first player to 10 points will win the scenario.

Finally, a Feast for Crows also adds new Westeros cards for the scenario only.