Labyrinth by Kate Mosse

This novel is basically a thriller set against the backdrop of the fourth crusade and a hunt for the Holy Grail. Mosse has added a unique twist to what the Grail actually means, but otherwise, it's pretty rote fiction. The labyrinth appears over and over again, but Alice can find out everything she needs to know about it from the internet. There are also three grail books, known as the Labyrinth trilogy, that remain rather opaque. By the end of the book Mosse apparently gets bored of her historical story and has a present-day character narrate it rapidly. I like the idea of witnessing history on which the book ends, but it's a little bit of a slog to get there.