Sunday evening, October 9th, 1216. King John is facing continued civil war and a devastating French invasion; treacherous times. We discover him crossing the tidal marshes of the Fenlands of East Anglia. He is about to lose England's crown jewels, his gem collection, and sackfuls of silver coins with his image on them: a treasure trove. What happened? What was he doing in that remote and windswept place? Why did he take the crown jewels with him? And why did he die so soon afterwards? Eight hundred years of searches by Fenfolk, academics, newspaper magnates, Victorian eccentrics and even an American research company have found nothing. No golden chalice, no pearl studied casket, no coins. Why? We follow King John at that vulnerable time, day by day, and reveal for the first time some surprising and interesting answers to the many questions posed by the mystery of his lost treasure.