From the Introduction:
Netheril seeks to win the war by the most expedient means possible: the conquest or destruction of Suzail. Most defenses are useless against the flying city of Shade Enclave, which even now inexorably approaches the heart of Cormyr. Should the Netherese manage to control the skies, they will have a nearly insurmountable advantage in the battle to come. There is someone who could even the odds, but only with your help, and only at a terrible cost. It is certain that not all those who volunteer for this special mission will return.
A Living Forgotten Realms adventure set in the skies above Cormyr for characters of the Paragon tier (levels 11-20). This adventure is a prequel to ADCP6-1 The End and the Beginning. You can play it on its own, but it can also be used as a way for public events to determine certain aspects of the situation at the beginning of the Battle Interactive.