Meeting in the camp - Main quest BG: Siege of Dragonspear Guide

The most important meetings will take place in the southern camp

You will reach Coalition Camp after solving the problem with the siege of Bridgefort in Boareskyr Bridge (M11 map). In the camp you won't encounter any enemies (at least yet) and you can consider it as your base of operation for the Flaming Fist (a place where you can rest and trade, meet all potential party members and unlock new side quests). Once you reach the destination, speak to Marshal Nederlock who will invite you to meet with the commanders in the southern tent of the camp. You can go there immediately - this will trigger a conversation with Marshal Nederlock, general Stonehand and Torsin de Lancie. You will receive a task to explore the caves under Dragonspear castle through which supplies are transported. You will also have to learn more about Caelar Argent's closest advisor - Hephernaan.

The hero will receive barrel of bwoosh! from Phossey

At the end of the conversation with the commanders you will be asked to meet with Phossey Dugdeep. Her camp is located in the northwestern part of the camp. Phossey will give your party Barrel of Bwoosh! and Stone Dowser. She will tell you to place the explosive in the most vulnerable part of the cave. The explosion should destroy part of the walls of Dragonspear castle.

Before you leave the camp, Torsin de Lancie will initiate a conversation with you as well. He will try convincing the party to poison the water and food supplies which are stocked in palace basement. This should weaken the enemies after attacking the castle later in the game. You can agree on this plan (in that case you will receive Poison of Terror) or you can decide that poisoning other people is not a humanitarian approach.