Main mission - The Grand Chapterhouse | Act 2 Dungeon Siege III Guide

After getting to Stonebridge go forwards all the time until you reach the Grand Chapterhouse (M18,X2). There, go to the basement (M19,X2) to fight a group of cursed soldiers. They are immortal - even if you kill them, they will return to life eventually. The only way of getting rid of them for good is taking the book from the pedestal in the middle of the room (M20,1). Proceed identically in all other rooms, however you will have to pull some levers to reach them (M20,2).

Don't bother fighting the enemies, just run for the book.

After you collect all five books, you should take them all to the shelf (M19,2). In order to reach it, you have to go through the secret passage behind the bookshelf (M19,1).

It's better to choose Meister first - you will have to complete both missions anyway.

A portal will open - Odo and Guiscard will come through it, giving you two more missions: Majority Rules and The Tumbledown Court. You have to decide which mission will you take on first - Majority Rules takes place in Stonebridge, so it's better to start with it.

M18 - Entrance to Stonebridge

M19 - The Grand Chapterhouse: upper floor

M20 - The Grand Chapterhouse: basement