Rome, present day: David Lowe arrives to research myths and folk tales. Studying in a library that seems to have as unusual a personality and history as it's Custodians. Parthia, second century A.D; Marcus Junius Silanus, far ahead of the legions of Emperor Trajan, explores the dead city of Persepolis and unwittingly unleashes a force more deadly than any the Roman Empire has had to face before. Both discover that, sometimes when you push into the unknown, it's been waiting for you.