This is a story set partly in medieval, partly in modern times, with two irrepressible heroines, modern educated English Alice and aristocratic medieval Cathar Alaïs (both quite incapable of following rules or doing what they are told), not to mention the sexy Cruella-figure Marie-Cécile de l'Oradore and her medieval counterpart Oriane (At Blagnac airport in Toulouse, the security official paid more attention to Marie-Cécile do l'Oradour's legs than the passports of the other passengers.) The two stories run side by side through the book, opening 4th July 2005, jumping back to Carcassona in Julhet 1204 (the author uses Occitan words, the langue d'oc, wherever possible) then alternating, two or three chapters of one with two or three chapters of the other.
The links are, firstly, Alice, who is apparently a reincarnation of Alaïs, and relives scenes from Alaïs' life in her dreams; and secondly, a certain Audric Baillard, who is a Cathar historian in the modern story, but has been alive since the 13th century thanks to the elixir of life which is one of the benefits of contact with the Grail. (Yes, you guessed it: that's what Marie-Cécile and Oriane are after!)
NOW, Alice - quite by chance (but as a direct result of deliberately ignoring instructions) - uncovers the cave where Alaïs died and a sacred book and a secret ring were lost along with her: the ring with the labyrinth engraved on the inside which was worn by all guardians of the Noublesso de los Seres. This discovery leads to mafia-style plot and counter-plot by those (led by Marie-Cécile) who still maintain the secret traditions of the Noublesso, and a militant Catholic group who will do anything to stop them.
THEN, Alaïs, lives in Carcassonne, in the heart of the Cathar country, when the Albigensian Crusaders led by Simon de Montfort, arrive, bent on destruction. In this book, authentically, they are seen as foreigners, "the French" (as the French approach We will be ready for the French when they come), an invading army, their greed for land being exploited by the Church and the Inquisition in order to rid the world once and for all of the popular Cathar heresy.
The Inquisition was founded to extirpate the Cathars [Audric tells Alice, who had thought the Inquisition was a Spanish creation]. The terror began. Inquisitors roamed from town to town as they pleased, accusing, denouncing and condemning. There were spies everywhere. There were exhumations so corpses buried in holy ground could be burned as heretics. By comparing confessions and half confessions, the Inquisitors began to map the path of Catharism from village to town to city. The Pays d'Oc began to sink beneath a vicious tide of judicial murder.
Alaïs' father is one of the five guardians of the Noublesso, responsible for guarding the three sacred books. He explains to Alaïs, who is being made responsible for one of the books following the murder of old Simeon, a Jew from the Holy Land:
'Always, the Navigatairé, the leader, is supported by four initiates [...] Christian, Saracen or Jew, it is our soul, our courage that matters, not blood, or birth, or race. It also reflects the nature of the secret we are pledged to protect, which belongs to every faith and to none.' He smiled. 'For more than two thousand years, the Noublesso de los Seres has existed though not always under that name to watch over and protect the secret. Sometimes our presence has been hidden, other times we have lived openly.'
Then her father, too, dies, and everything devolves upon her.
Definitely one of the best time-slip/reincarnation stories I have ever read.