From the introduction:
Long ago, in an age forgotten, the four pantheons shaped the world. However, in their petty squabbling, they created the Snarl – a being of pure chaos that slew the Eastern Gods and devoured all of Creation in 28 minutes. The three remaining pantheons (North, South, and West) created a new world as a seal around the Snarl, a prison it could neither perceive nor escape – at first. Aeons passed, however, and tears began to open in the fabric of reality, creating five rifts in the world. A party of brave adventurers went on a grand quest to seal these rifts, and thus were the five great Gates forged. Since the fateful day the first Gate fell, a powerful Sorcerer and his goblin accomplice have searched for the remaining Gates, that they may enact a powerful ritual to seize control of the rifts in reality kept in check behind them. However, that doesn't really matter much right now, because the people whose adventures you're following aren't really aware of all of that yet. In three years' time, you'll find yourself somewhere around the adventures of The Order Of The Stick.