When we last left Jack West, Jr., he was plummeting into a fathomless abyss and his quest to save the world from Armageddon appeared doomed. But all hope is not lost. After an astonishing escape, Jack regroups with his trusty team. Racing to rebuild the fabled "Machine," they discover an ancient rhyme about five mysterious unnamed warriors -- great historical figures whose knowledge will help unlock the secrets of the Machine and its long-lost "pillars."