You are a mage form the Magi Circles and you have just been told that the Evil Squares have found the Orb of Wonders. The Evil Squares care not for it's power, but only in it's beauty (they're not too bright). The Magi Circles have given you the task of fighting through their ranks to retrieve the Orb of Wonders before the Evil Squares can use the Orb's power.
This is a video of the last major update to the game, Location Based Enemy Spawners! The idea is that whenever you walk into a new "Stage" a bunch of enemies will spawn and you have to defeat them all in order to go to the next stage.