From the publisher's website:

Recruit heroes, gather artifacts, and undertake heroic quests. Each of the eight gods of Olympus leads a family of cards with specific powers. The 168 cards of Elysium are the heart of the game. They represent heroes, items, powers, and the gods who will intervene in the quests and legends of the players. Each card is affiliated with one of the eight gods present in the game, which is represented by a small icon and a color. Moreover, it has a level (from 1 to 3), and an activation acquisition condition (one or two colored circles). All cards have an activation symbol, which determines when the card’s power may or must be used. The power itself is described both as a series of icons and in writing. At the back of each card is a citizen, a kind of joker without any powers but which can be sent to the Elysium to complete a legend… at the risk of making the gods discontent. During each epoch of the game (and there are five of them), the players must acquire 3 cards and a quest. The quest determines the play order of the following phases, grants gold and victory points, and allows the player to perform a certain number of transfers to the Elysium. The choice of quest for each of the epochs is therefore very important. Moreover, an unfortunate decision (or clever opponents) can very well deprive you of that choice. - If no quests are available for you, you’ll receive a flipped-over quest tile, which we’ll call an unfinished Quest. You’ll play the following phases last, and you’ll only get a single Gold and one transfer.