M7 - Galafor/Acatha
1 - Tirin's Rest
2 - Reedsong Inn
3 - Tirin's Sanctuary
4 - Cergen & Brand Mercantile
5 - Locksmith
6 - Sacred spring
7 - Serabel Nareen
8 - Adarus
9 - Kandir's corpse
10 - Fae urn
11 - Peculiar green stone
12 - Lapidus Root
13 - Gloamthicket
14 - Ancient Windstone
15 - Skycrown
16 - Burren Cove
The inn-keeper Meyra Maun in the Reedsong Inn M7(2) will ask you to donate some gold for the army. If you do it, you'll receive another task.
You need to take the woman's purse and take it to the nearby sanctuary M7(3).
After doing that, wait inside until midnight and a thief will appear.
After a short conversation you will be able to either tell of his deeds and let him go free. In both cases you will only receive experience points.
Gwastl Brad from the "Cergen & Brand Mercantile" M7(4) will tell you the secret of a certain prisoner. If you use persuasion, you will also learn that he's being held in the Burren Cove below the local sanctuary M7(3). Otherwise you will have to learn this from the citizens: White Nila Kerna, Priestess Corelon, Meyry Maun (inn-keepers) and Floriana Brennaca.
Having done that, head to the sanctuary and break into Burren Cove.
Burren Cove map
1 - Adar
2 - Exit
Inside the cell on the left you will find the prisoner you're looking for. Speak to him to learn that the keys are in possession of Nil Kern, while the words that can remove the magic barrier are known by Priestess Corelon.
You can obtain the key in two ways, either by stealing it from Nil's pocket, or persuading the man to give it to you himself.
The thing with Corelon's spell won't be that easy. The woman won't want to admit to imprisoning the Fae. In order to obtain the spell words, return to the sanctuary and enter the upper floor. On one of the desks you will find a book with the proper spell.
After learning it, return to the Burren Cove and free Adar. In return you will receive a magical crystal.