The Elder Scrolls IV: Oblivion takes place in the central province of Tamriel, Cyrodiil. The Emperor has been killed by unknown assassins, the throne is empty. In the absence of a legitimate monarch the gates of Oblivion open, and demons invade Cyrodiil, attacking towns and the population. The player's task — to find the missing heir to the throne and restore peace and calm to the chaos of Tamriel's war.
In keeping with the traditions of The Elder Scrolls, the player is given the opportunity to pursue the main quest at their own pace, not restricting themselves in time, using numerous opportunities to explore the vast world. The hero can become a member of many factions — for example, the Fighters' and Mages' Guilds, follow quest lines associated with each of them, and reach the higher ranks of their hierarchies.