From the front page of the PDF:
The city is overrun by a plague of shadowy creatures. You are tasked with rescuing the Cormyrean ambassador from legions of undead. Will you be able to save the ambassador without becoming one of the living dead yourself? A Living Forgotten Realms adventure set in Urmlaspyr for characters of the Heroic tier (levels 1-10). This adventure concludes the Trouble in Urmlaspyr Major Quest.
This adventure is the conclusion of Chapter 1 the Desolation series. Chapter 1 includes four Heroic tier adventures leading up to this conclusion. The other parts are SPEC4-5, CORE4-3, CORE4-4, and CORE4-5. You can play the Chapter 1 adventures in any order, but you should try to play them with the same character, and we recommend that you play the first four adventures before you play CORE5-1. The Desolation series also includes Paragon tier adventures (starting with SPEC4-6). It is not expected that a player can follow both tracks with the same PC.