Orion £9.99 pp531

This weighty Holy Grail adventure story comes hot on the heels of The Da Vinci Code, Dan Brown’s bestselling thriller. It is, by anyone’s standards, an admirably bold endeavour.

The action begins in the present day: Alice Tanner, a young British woman, is a volunteer on an archeological dig in the mountains outside Carcassonne in France, a “place of secrets” that has “seen too much and concealed too much to be at peace with itself”. These secrets (which will be unravelled over the next 500 pages) are abruptly brought to Alice’s attention when a boulder comes loose and crashes down the mountain, exposing a cave. Alice is drawn inside to find two ancient skeletons that represent, it turns out, both her heritage and her destiny.

We then shoot back 800 years to medieval Carcassonne. Here, Alaïs, a headstrong 17-year-old, has to protect an ancient book that turns out to be part of a “Labyrinth Trilogy” containing the secrets of the Holy Grail. Alaïs, as independent and fearless as her modern counterpart, has to make sure that her precious charge does not come into the wrong hands. Of which there are many: evil schemers abound, and the scariest of them all is Alaïs’s sister, the ruthless temptress Oriane. The complexities of this quest, told in two parallel stories — one historical, one modern — are indeed labyrinthine.

This is a novel clearly fuelled by an authorial obsession with a history, region and concept. The settings are evocative and although the historical dialogue can feel mannered there are head-spinningly gory descriptions of crusaders butchering entire villages, burning innocent Cathars at the stake, beating and torturing people and slitting throats. There are also some powerful dramatic scenes: the climactic moments where the good and evil women meet and battle it out are particularly compelling.

But there are downsides to this complex historical subject, too. Towards the end of the book, just as it seems there will never be a comprehensible explanation for what is going on, a wise old character sits Alice down and explains to her the origins and nature of the Grail, ranging through Old French poetry, Ancient Egyptian hieroglyphs, ninth-century Arab alchemists, the crucifixion and Napoleon’s expeditions in north Africa. His lecture is all-inclusive: “In the last quarter of the 12th century,” he starts, “lived a poet called Chrétien de Troyes. His first patron was Marie, one of the daughters of Eleanor of Aquitaine, who was married to the Count of Champagne. After she died in 1181, one of Marie’s cousins, Philip of Alsace, Count of Flanders, became his patron . . . ” But the device, while helpful, disrupts the fictional pace. And this, of course, is the book’s central challenge: how to elucidate and educate the reader without ruining the action.

Overall, the message that “through the shared stories of our past, we do not die” is movingly proclaimed. That life’s true “elixir” is love, “handed down from generation to generation”, becomes beautifully clear and makes an uplifting ending to this intriguing, occasionally frustrating, but, above all, passionate book.

Available at the Sunday Times Books First price of £9.49 on 0870 165 8585 and www.timesonline.co.uk/booksfirstbuy

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