Young King Henry wages war on France. But, tainted by his father's crimes, and with enemies among his own men, he must confront the difficult responsibilities of kingship. In rousing speeches, first at the siege of Harfleur where he urges his men 'Once more into the breach', and again on St Crispin's Day before the Battle of Agincourt, Henry rallies the English troops to spectacular victories which change the course of history. But even with the battles won, the war is not yet over - for to make safe his success, Henry must secure a marriage with the French princess, Catherine of Valois. And can triumph in France prevent civil war in England?