The second star stone you interact with will open the teleporter to the Hall of Heroes (in the main room it is the one left of the observatory teleporter).
Odd ...
I'm far enough along that Evelyn is gone and I did the quest where you have to choose between the two guys needing healing. If I understand correctly, that is the other place to interact with the second stone (besides the murder scene).
Either something is bugged, or they make it pretty easy for you to end up not being able to get a companion back after dismissing one. It seems rather bad design that you can easily pickup a companion, but if for some reason if you dismiss one, you could be locked out from getting the person back. Seems like they should return to an area that only needed to be unlocked as far as when you picked them up. *shrug* Needlessly frustrating.
