From the first page of the PDF:
The skyships of the Five Companies could help Cormyr combat the growing menace of Netheril. Unfortunately, a large portion of the fleet is currently in drydock. To repair the ships damaged by the treachery of Seric Vargenos, the Five Companies need materials from far-off Halruaa. Only you can gather those materials in time. A Living Forgotten Realms adventure set in Halruaa for characters of the Heroic tier (levels 1-10).
This adventure is connected to SPEC5-4 and continues the story started in ADCP5-1. It is also a lead-in to ADCP5-2. This adventure is part of Chapter 3 of the Desolation series. The series has both Heroic and Paragon tier adventures; it is not expected that a player can play both tracks with the same PC.