Emania. Capital of Conachúr mac Nessa’s Ulster kingdom; located near modern-day Armagh in Northern Ireland, where Conachúr has Deirdre raised after it is prophesied that a retainer’s child named Deirdre, “Troubler,” will bring evil to Ireland. The girl’s witchlike foster-mother Lavarcham teaches her respect for the king, but the attempt to train her in isolation from human society fails when Deirdre makes friends with the old guards in the castle in which she is kept. As she develops a sense of herself and makes her first forays into the outside world, she meets Naoise and his brothers, young warriors related to and serving under Conachúr. Deirdre and Naoise become lovers.
*Scotland. After Deirdre coerces Naoise into elopement, she and her lover and his brothers go to Scotland, turning their backs on their community and civilized space. While a free life in the Scottish wilderness brings joy, the fugitives cannot rest, for Deirdre’s beauty has attracted the king of Scotland.
Red Branch. Conachúr’s lavishly decorated Ulster fortress, in which he has Deirdre and Naoise stay after their return to Ireland. When Conachúr breaks his promise and lays siege to the building, it becomes a death trap. Deirdre and her warriors make brave sorties among the troops before the six great doors in the belief that Fergus will come to their rescue. Eventually the Red Branch is burned down, and the defenders must flee. The forces thus set in motion conclude in the cattle raid of Cooley and the apocalyptic clash between Ulster and the remainder of Ireland.