July 1209: in Carcassonne, a seventeen-year-old girl is given a mysterious book by her father which he claims contains the secret of the true Grail. Although Alaïs cannot understand the strange words and symbols hidden within, she knows that her destiny lies in keeping the secret of the labyrinth safe... July 2005: Alice Tanner discovers two skeletons in a forgotten cave in the French Pyrenees. Puzzled by the labyrinth symbol carved into the rock, she realises she's disturbed by something that was meant to remain hidden. Somehow, a link to a horrific past - her past - has been revealed.