The two texts tell of battles fought by the Tuatha Dé Danann, the first against the Fir Bolg, and the second against the Fomorians.
It begins with the children of Nemed, an earlier group of inhabitants of Ireland, leaving for Greece to escape their oppression by the Fomorians.
The Tuatha Dé Danann, led by their king, Nuada, come to Ireland in three hundred ships from the islands of the north.
A truce is called, and the Fir Bolg are given three options: leave Ireland, share the land with the Tuatha Dé Danann, or continue the battle.
[3] Seven years later Bres dies after taking a drink while hunting, and Nuada, having had his arm replaced, is restored.
Because of his ancestry Bres oppressed the Tuatha Dé Danann, making the noblest of them do menial work, imposing heavy tribute, and failing to show the level of hospitality expected of a king.
He is deposed as king, and Nuada, who has had his arm replaced with one of silver by the physician Dian Cecht (whose son Miach caused flesh to grow over it), is restored.
Bres is found alive in the aftermath of the battle, and is spared on the condition that he teach the Tuatha Dé Danann how to plough, sow and reap.