The aim is to reach the target on the victory card you have drawn at the beginning of the game. The victory condition may be one of the following:
Archmage (10 followers, 40 mystic power, 10 gold),
City (40 followers, 10 mystic power, 10 gold),
Hoard (10 followers, 10 mystic power, 40 gold),
Balanced (20 followers, 20 mystic power, 20 gold)
By using cards you try to reach the above options, as well as hinder your opponent. Each 10 of followers make you draw an extra card, each 10 of mystic power make you keep an extra card and each 10 of gold gives you some other advantages. The different levels also gives you other advantages.
With the resource cards you may either increase or decrease the values on whichever player you want. There are also spell cards, deity cards and event cards, which may affect the game.