In the cellar, that you enter from the hatch behind the apothecary's desk in the blighted village, I found the cabinet that I assume slides and reveals a passage. I am able to clip the camera through the wall and I can see everything behind it, the grove and the ... workshop... I'm even able to cast mage hand behind it and run around, but I have not found a way to open it. The inability to open it could obviously just be me not able to figure out the puzzle yet, I'm more worried about the clipping and seeing secrets before you should be able to.
