Where do I find Gadwall? It's so easy! I wasted a lot of time on this so here's how you do it. Talk to Dethmold in the tent. He'll insist that you "prepare" to the ritual and Geralt suggests drinking Gadwall. As soon as you exit the tent there is a man sitting outside to your right. He is literally in front of the tent Dethmold is in and it seems he's the only one who has Gadwall. Just buy some off him, then go into meditation mode and drink it.