The forbidden Citadel at the heart of the ancient Turkish city of Ruin opens its gates for the first time in history. Why now, after centuries of secrecy? A deadly disease has erupted within, and threatens to spread beyond its walls. Infected charity worker Gabriel Mann may hold the cure - but can one dying man stop an epidemic? Without him Liv Adamsen, a former journalist, is vulnerable, surrounded by strangers in the desert oasis that is her new home. Liv, however, has far bigger concerns than just her own life.