AD 256. Pope Sixtus passes on relics belonging to Christians being persecuted to a follower who entrusts it to the Jewish community in Spain. 1684. Samuel Pepys goes to Tangier in an attempt to retrieve an incredible treasure that has resurfaced after more than a thousand years. Present-day. Jack Howard and his team are excavating a 17th-century shipwreck and realizes that the wrecked cargo contains clues to an ancient mystery - the lost treasure of Christendom, the fabled Holy Grail.