Allies is the 14th expansion to Dominion. It has 400 cards, with 31 new Kingdom card piles. There are Allies that will do Favors for you, and split piles you can rotate. It cannot be played by itself; to play with it, you need the Basic cards and rule book (Dominion provides both). Dominion: Allies can also be combined with any other Dominion expansions you have.