While excavating in the mountains of Kurdistan for evidence of an ancient, widespread flood, Dr Maria Sombarte instead unearths a relic she had spent much of her career discrediting. Now, she must find her colleague and rival Anthony Waterman, who has vanished in the darkness of the Brazilian Amazon.

Meanwhile, in Russia, Chief Inspector Vassallo is tasked with finding the terrorist responsible for the attempted assassination of a bishop, favoured by many to be chosen as the next Pope.