Richard the Second is losing his hold on the crown and Henry of Bolingbroke, previously exiled by the king, returns to England to claim it. Richard is deposed and dies mysteriously, murdered some say on the orders of Bolingbroke, now King Henry the Fourth. But Henry finds the crown harder to hold onto than it was to win. He is beset by enemies, hampered by disease, and concerned about the rebellious behaviour of his son. Dominating the court and with his eye on the crown is Harry of Monmouth, whose reckless conduct in low-class taverns with his crony Sir John Oldcastle causes scandal. When the king dies, Harry became King Henry the Fifth, and the change is dramatic for both him and Oldcastle. The licentious youth becomes a great king, and Oldcastle, the rake, turns into a religious reformer. Oldcastle dies a martyr and Harry becomes the conquering hero of Agincourt.

The Star of Lancaster is in the ascendant. Harry has brought France to her knees and married her princess. It seems that the long war was at an end. But a greater enemy than the French awaits Harry ...