Privileged daughter of William Marshal, Mahelt marries Hugh Bigod, heir to the earldom of Norfolk. But when King John sets out to subdue the Bigods, Mahelt faces the worst alone, knowing neither she, nor her marriage, are likely to survive. A story of emotional power set against the road to Magna Carta and the fight to bring a tyrant king to heel, To Defy a King is Elizabeth Chadwick at her best.