In this card game based in H.P Lovecraft's Cthulhu Mythos, you play an investigator (represented by a double sized card that has your stats, special abilities and keeps your story organized) who must complete stories without going insane. From a deck of at least 52 cards you draw 13 and take turns playing one at a time so it moves at a brisk pace. You stock your deck with at least 20 points of stories (usually 3 or 4) and try to get the required cards into play. As an example The card 'A Day in the Life of a M. U. Student' requires you to visit 3 Different Miskatonic University Locations, cast a spell, summon a monster, go to a country site and play an ally of the opposite sex. When you have fulfilled the conditions you score the card and gain sanity. In this card's case you score 8 points and gain 2 sanity.
The types of cards you have are locations (you almost always occupy one), allies, monsters, events, tomes, spells, artifacts and adventures. A round lasts until there are two passes, at which time all monsters played fight each other then go after the investigators to disable their allies or reduce their sanity. You can throw allies in front of the monsters as cannon fodder to protect your investigator. You then decide what cards you are going to keep in your hand (each investigator has a minimum and a maximum number of cards that must be kept) and draw back to 13 for the next round. Because of this you blow through your deck very quickly and you will go through it a couple of times in most games.
There are also some very nasty phobias and events to play on your opponents to interfere with their strategies. There is a lot of interaction and the Lovecraftian atmosphere is keenly felt.