"The Serpent's Shadow" is the third book in Rick Riordan's Kane Chronicles series, which follows siblings Carter and Sadie Kane as they navigate the world of ancient Egyptian magic. In this installment, they face the powerful Apophis, the serpent of chaos, who threatens to plunge the world into darkness. The story combines adventure, mythology, and humor as the Kanes seek to stop Apophis before he can rise. They enlist the help of friends and allies, including Bast, the goddess of cats, and Anubis, the god of the afterlife, to confront their greatest challenge yet.