They've sailed on the Santa Maria, defended famous cities from Vikings and Mongols, and come face-to-face with some of the greatest figures in history. Now, at long last, Dak, Sera, and Riq travel back in time to the moment it all began. Their mission: to save the life of young Alexander the Great. But they are not the only time travelers in ancient Greece. An epic battle against their most dangerous foe awaits them . . . and history will be written by the victors.