In 12th-century Ireland, provincial kings vie for supremacy. When two of these power players drive a rival into exile, he seeks help from Henry II, the Anglo-Norman king of England. Henry's vassal Strongbow and other Norman allies then invade Ireland with frightening power.

Following the course of the invasion, as Strongbow wins victory after victory. In 1171, Henry II himself arrives to takes control of Ireland, and grants land there to settlers from Britain. Now, archaeology and cutting-edge science reveal their fascinating lives.