Tombstones

Remember where you got the toymaker stuff last year? Same person.

In the Library map, very top, through the door to the right of the fireplace.

Actually I looked around, there's another way in. In one of the upside down rooms, you go through a lower right room into a barren room (the correct one has two portals, one in the middle, one on the right) and you just have to jump up a pathetic jump quest to get to Jonas.