Each one contains everything you need for a two-player game of Magic. There are two Gatecrash booster packs and two semi-randomized "decks" of 22 cards. Each one is associated with one of the Gatecrash guilds: Orzhov, Dimir, Gruul, Boros, and Simic. Each player takes one, then opens a booster pack and selects up to five cards to add. Then each player has a deck of 22 to 27 cards. And then the battling begins!