From the box:

"Now you can play Cooperatively! Expansion 3 adds two decks that allow players to play together against the hordes of the Undead. Each player has a unique goal. Action Cards are available to help the players achieve those goals. Also included are 4 New Locations and 2 New Character Boards.

Included in the box:

• 2 new character boards
  
• 8 Personal Goal cards
  
• 16 Action cards
  
• 4 new location cards