This is not a standalone game. A copy of Dominion is required to play. 

Intrigue is the 1st expansion to Dominion. It has 300 cards, with 26 new Kingdom cards. There are victory cards that do things for you, underlings that give you a choice as to what they do, and a variety of other cards.

Something’s afoot. The steward smiles at you like he has a secret, or like he thinks you have a secret, or like you think he thinks you have a secret. There are secret plots brewing, you’re sure of it. At the very least, there are yours. A passing servant murmurs, “The eggs are on the plate.” You frantically search your code book for the translation before realizing he means that breakfast is ready. Excellent. Everything is going according to plan.

This is the second edition of Intrigue. Compared to the first edition of Intrigue, six cards were replaced and one added.  It no longer has Base (money, victory point cards, etc) and thus is no longer a stand-alone expansion. If you want to expand the game to be able to play with 5-6 players, use a set of Dominion Base Cards.