AD 70: a group of Roman soldiers crossing the Sahara desert is destroyed by a ferocious and mysterious presence hidden in a solitary tower at the extreme borders of the sea of sand. The sole survivor, Etruscan seer Avile Vipinas, is inexplicably saved by the sound of his silver sistrum. Nineteen centuries later, young American scholar Philip Garrett discovers the house of Avile Vipinas in the underground ruins of Pompeii, sealed by the earthquake of 79 AD. Who is the ancient civilization, older than the oldest known, that created this tower? What is its purpose?