Oblivion is the fourth part of the acclaimed The Elder Scrolls series. It is set in the high fantasy world of Tamriel, in the Septim Empire. The emperor was recently killed along with his sons, except one that was hidden far from the capital. Before he died, the emperor gave his Amulet of Kings to the protagonist, a prisoner whom the emperor believed to be a future hero he saw in dreams.
The main character is fully customizable. His or her character class race, gender, age and other attributes are chosen by the player. His quest is to escape prison and find the royal heir. However, since the game is open-world, the player may abandon the central storyline and just wander around Tamriel. You can complete a variety of side quests, join various guilds and factions, or just fight monsters to gain experience. There's an option of "fast travel" that allows you to instantly move to an already discovered location.
Game of the Year Edition also contains two expansion packs: Shivering Isles and the Knights of the Nine that expand the game’s storyline. The packs introduce several new locations, two additional factions (the Court of Madness and Knights of the Nine), and a number of new armor, weapons and other items.