The rebellion promoted by the Percy family against their former ally King Henry IV has been heavily crushed at Shrewsbury. The rebels were weakened by the defection of the armies promised them by Northumberland and Owen Glendower, and greatly outnumbered by the King's forces. Their leader, the gallant Hotspur, has been killed in single combat with Prince Hal. Conflicting rumours reach Warkworth in Northumberland, where the Earl is eagerly waiting for news of the battle and of his son.