The final thrilling instalment in award-winning author and Percy Jackson creator Rick Riordan's Kane Chronicles trilogy! Is their inherited magic enough to battle against the most powerful mythical forces that Egypt's gods have to throw at them? Carter and Sadie Kane, descendants of the magical ouse of Life, are in pretty big trouble. Despite their bravest efforts, Apophis, the giant snake of Chaos, is still threatening to plunge the world into eternal darkness. Now the Kanes must do something no magician has ever managed—defeat Apophis himself. No pressure there then. Battling against the forces of Chaos, their only hope is an ancient spell—but the magic has been lost for a millennia. Will they find the serpent's shadow, or will they be led to their deaths in the depths of the Underworld?