The Key

It's been several weeks since the Citadel of Ruin, south east Turkey, was breached. With the first prophecy seemingly fulfilled and the Sacrament liberated, the monks no longer need to remain isolated from the world. But in Rome, the news is met with horror and an emergency meeting of Cardinals is called. Could the release of the Citadel's secrets mean the end of the Church?
Liv Adamsen is still shaken from her experience in the heart of the mountain. As a whispered word, 'KuShiKaaan', the key, echoes through her head, heralding terrifying blackouts, it becomes clear her work is not yet done. Meanwhile, Gabriel Mann has been released from prison and returns with his mother Katharine to their charity's headquarters in Rio. There they examine Oscar's private papers and make a startling realisation that the prophecy was not complete.
Inside the Citadel, Athanasius and the remaining monks must decide the future of the church. But with the arrival of a Cardinal from Rome, and the return of the lone surviving Sancti, both determined to restore the old order, lives are once again at stake.
Meanwhile in the Iraqi desert, a stone tablet engraved with ancient text forming the shape of an upside Tau has been recovered by a group of warriors. Along with revelations concerning Gabriel's father's death, it becomes clear that the events of Sanctus were just the beginning. As the world is battered by biblical weather and extreme famine, and a plague sweeps through the mountain, Liv and Gabriel must again join forces to fulfil an ancient prophecy...