The Venetian Betrayal: Book 3 by Steve Berry
Cotton Malone is back and the stakes were never higher: a deadly virus that could wipe out civilisation as we know it -- and a cure that lies buried in the past. The Venetian League, a secret group of 45 political and economic leaders from around the world, has joined forces with a coalition of former Soviet republics to create a potentially devastating biological weapon, a bird flu-like virus that has been artificially mutated to pass from human to human. Whoever develops the cure would control the future of global warfare. Yet that cure may have been discovered centuries ago, and if so the clue to the location of the formula lies buried with Alexander the Great. When Cotton Malone's former companion Cassiopeia Vitt hears about it, she and Cotton join the hunt for Alexander's long-lost tomb, and what at first seems to Cotton a wild quest for the answer to a perplexing historical riddle becomes a harrowing fight for truth that has unimaginable repercussions, both geopolitical and terrifyingly personal.