This Dominion Adventures expansion introduces 30 new kingdom cards, including a number of ‘permanent’ ones that remain active in subsequent turns. There are also reserve cards, which you can save for later, and event cards, which allow you to purchase items other than cards, such as tokens that alter the effects of cards.
Dominion: Adventures can only be played in combination with Dominion or Dominion Intrigue. This is because you need the victory and money cards from those games.