From the introduction:
The Battle for Brindenford is more an event than a series of areas, though it does all take place within the city of Brindenford - the assumed base of operations for characters exploring the Dragon’s Delve. It is designed to give higher-level characters an opportunity to adventure within Brindenford again, and to flesh out the town further for groups that spend a lot of time there. While there is a short plot tying all of the ten entries of the Battle for Brindenford together, GMs running campaigns that aren’t ready for the higher-EL encounters of the Battle can still use many of the new characters and locations presented and simply not begin the more dangerous aspects of the struggle to control the town until their PCs are more experienced.