The player enters the realm as an event called the Greymarch is about to occur - in which the Daedric Prince of Order, Jyggalag, completely destroys the Shivering Isles. Upon entering the realm, the player has access to only one area of the Shivering Isles, called the Fringe. To gain access to the other areas, the player must defeat a creature called the Gatekeeper.
The player's entry into the realm coincides with the impending Greymarch, a catastrophic event in which Jyggalag will eradicate the Shivering Isles. Initially, the player is confined to the Fringe, but must overcome the Gatekeeper to gain access to the other areas of the realm.