When Alfie’s mother falls gravely ill, doctors say only a miracle can save her. Having only just moved to the seaside town of Tudllan, Alfie and his dad desperately search to find a cure. Almost at the point of giving up hope, Alfie hears of a local legend about a sacred cup, mentioned in an ancient book, the Book of Tudllan. Over one and a half thousand years earlier, Cai, a young slave, narrowly escapes with his life from a battle, having sworn to his dying master, one of the last Roman centurions in Britannia, to deliver a mysterious bundle to a man named Gwion, at a remote sanctuary. He later learns that the bundle contains a sacred cup with healing powers, also known as the Holy Grail. Was that sanctuary Tudllan, and does the ancient Book of Tudllan hold clues to its secret resting place? Alfie, and his friend Melanie, must race against time to decipher the book’s clues in the hope of finding the cup, before a gang of ruthless treasure hunters do. Alfie believes that it is the only thing that can save his mother. But does the cup really exist, is the legend true and can it be found in time?