Amy and Dan continue to search for ingredients for a serum that can stop J. Rutherford Pierce from using the Cahill family's main secret against them. While dodging Pierce's henchmen, the friends must embark on a perilous journey that will take them from one of the world's hottest regions to the icy reaches of the Arctic Circle. But the real tragedy will be what Dan has to endure when he learns what it's like to be betrayed by his own sister.