From the Quickstart FAQ:
Fortunes Wheel is a tabletop role-playing game or 'RPG' that uses tarot cards instead of dice.
Players create characters, settings, creatures and items using tarot cards drawn from a deck/ The cards are used to give both a numerical value and an interpretive one for four attributes that correspond to the four elements of Fire (for will power/ego and creativity), Earth (for the physical body and material word), Water (for emotions and the subconscious/id) and Air (for the mind and thought).
These have a numerical value from 1-10. This gives a score for elemental energy. The higher its value the more powerful it is and the more it represents an idealised form of the element.
To resolve actions in the game such as combat or completing a task you test a combination of one of these four elements along with a card drawn from the deck against an opponent's element and a drawn card - the higher result beats the lower one and any excess becomes damage against elemental energy. Once an elements energy has been depleted it no longer functions.
The cards can also be used to create an extra layer of meaning in the game. Each card has a traditional meaning and you can also build your own interpretation of them based on the images on the cards and any associations players make with them. You can also apply this meaning to any results in the game, enabling a really powerful and effective story aspect you just do not get with most games.
Players also have a pool of Fortune Points that they can use to manipulate results and events in the game.