Professor Robert Langdon is called to help investigate the death of a scientist in a high security facility where the victim is branded with the ambigram Illuminati. This leads him, along with the scientists daughter, Vittoria Vetra, to the heart of Vatican City where a canister of antimatter was stolen from the lab has been placed, and will go off at midnight. The Vatican is about to close for the conclave due to the recent death of the Pope, but the prefretiti, the 4 cardinals who are unofficially chosen as the front runners for the papacy, have disappeared. It is now up to Langdon and Vetra, along with the Swiss Guards and the camerlengo, to find the cardinals before midnight as they have been warned that one cardinal will be killed in each hour leading to midnight in a very public place, with the 4 known ambigrams of the Illuminati branded on their chests. An ancient brotherhood that may still be active, a race against the clock to save the cardinals and to find that antimatter before it levels Vatican City, and other twists and turns will keep you reading long into the night.