Under a dark cloud, Caledan Caldorien left the Harpers seven years ago. Now a mysterious and beautiful messenger from the secret society convinces him to undertake one final, reckless mission. Iriaebor, City of a Thousand Spires, has fallen under the sway of the evil network of Zhentarim. With a fellowship of old friends, Caledan must seek an ancient magic to counter the dark conspiracy of the Harpers' nemeses. Awaiting them all is a terrible secret that lies beneath the city.