Where's Wilson? - Baldur's Gate 2 Side Quest
Where's Wilson is a side quest that begins by speaking with Zaviak at the Hidden Refuge camp. The Hidden Refuge zone is part of the Enhanced Edition for Baldur's Gate 2 and can only be accessed after progressing far enough in Neera's Companion Quest. You will also have to recruit Neera into your party to access the Hidden Refuge.
Important: You can only complete this quest during a part of Rasaad's Companion Quest. If you complete Rasaad's quest then you'll lose access to Wilson.
For this quest you are tasked with locating a bear named Wilson which you'll have to bring back to Zaviak in the Hidden Refuge. You can find Wilson on the Heretic Temple map during Rasaad's Companion Quest; you have a very small window to recruit Wilson to your party and if you miss this opportunity you'll never be able to finish this quest.
Once you have complete Rasaad's quest Wilson will leave this map but (at least for me) Jolstead stuck around. Both of these NPCs are needed to recruit Wilson, it's during your dialogue with Jolstead that you're actually able to recruit him into your party.
When you visit the Heretic Temple map you will need to speak with Wilson who is the Grizzly Bear in a cage outside the entrance of the temple. This is very important!! If you do not speak with Wilson first you will not be able to recruit him! After speaking with Wilson and learning his name Jolstead will begin dialogue with you during which you'll be able to purchase Wilson from him.
You can lower the cost of Wilson from 1000G to 500G if you wish through a little haggling. Either way once he's purchased he'll leave his cave (or get stuck and teleport) to the northwestern portion of this map. Return to the same area you entered this map from and you will find Wilson waiting for you. Talk to him here to recruit him into your party for realsies then you can take him to see Zaviak and complete the quest.
Step By Step How to Complete the Quest:
1. Accept the quest from Zaviak
2. Recruit Rasaad & progress Rasaad's Companion Quest to the part where you arrive at the Heretic Temple
3. Outside the temple talk to Wilson in the cage then talk to Jolstead to free Wilson
4. Find Wilson in the northwestern portion of the map where you zone in/out at and talk to him to recruit him
5. Take Wilson to see Zaviak in the Hidden Refuge
Now, let's say that you already screwed up this quest and completed the Heretic Temple. Wilson is gone and there seems to be nothing you can do to fix this... Thankfully, there is! If you enable Console Commands for your game and press Ctrl + Space you'll open up the CLUA Console (pictured above).
Copy and paste the line below into the console and this will spawn Wilson whom you'll be able to talk to and progress the quest like normal.