From the introduction:
As a dull orange sun breaks over the blood-stained banks of the Brena River, the wheel turns on year 582 of the Second Era, the 13th day of Morning Star. Almost six centuries ago, Emperor Reman III and his line were murdered, joined in death soon after by the treacherous regent Versidue-Shaie and his son Savirien-Chorak. With no successor, the Empire dissolved into infighting. Worsening the situation, Reachmen lead by Durcorach the Black Drake captured Cyrodiil, throwing the entire Imperial Province into ruin. Pretender to the throne Varen Aquilarios managed to loosen their grasp, but vanished while searching for the Amulet of Kings, the Emperor’s badge of office and an essential component in relighting the Dragonfires. No-one knows what happened to the savior of Cyrodiil. When he vanished, he took the last hopes of the dying Empire with him.