Thomas of Hookton is one of those archers. When his village is sacked by raiders, he escapes from his father's ambition for him to become a priest, and becomes an archer in the army of King Edward III. The King and his son, the Black Prince, are going to France with a great force of knights and men-at-arms; it is led by great lords, but it is the archers, the common men, who will decide the success or failure of the invasion.

Thomas, his previous world and promises forgotten, revels in the life of an army at war and, even among those fighting men, becomes known for his wildness and his fearsome skills. He falls in love with a Breton widow, one of the enemy and of a different class, and his pursuit of her makes him into a fugitive, hunted by the French and English alike. But an adversary rescues him, leading him into a world where lovers become enemies and enemies become friends. There, hidden beyond the horizon smeared by the smoke of fires set by the rampaging English army, a man from the past awaits him, a man who possesses something Thomas once made a sacred promise to retrieve.

And this shadowy enemy could harness the power of Christendom's greatest relic, the grail itself.