From the No.1 internationally bestselling author comes the third heart-stopping adventure exploring the incredible history, legends and hidden secrets of Carcassonne and the Languedoc. Set during World War II in the far south of France, CITADEL is a powerful, action-packed mystery that reveals the secrets of the resistance under Nazi occupation. While war blazed in the trenches at the front, back at home a different battle is waged, full of clandestine bravery, treachery and secrets. And as a cell of resistance fighters, codenamed Citadelle, fight for everything they hold dear, their struggle will reveal an older, darker combat being fought in the shadows.