When a murder of a physicist, Father Silvano Bentivoglio, finds a symbolist, Robert Langdon and Vittoria Vetra, on an adventure for a secret brotherhood, The Illuminati. Clues lead them all around the Vatican, including the four altars of science, Earth, Air, Fire and Water. An Assassin, working for the Illuminati, has captured four cardinals, and murders each, painfully. Robert and Vittoria also are searching for a new very destructive weapon that could kill millions.