The "???" is not related to that quest, it's part of the final part of the "Reasearch ancient Culture" questline. The quest appears in the guild once the two previous parts are done and you have a reputation of at least 500.
Having the quest "In Search for Power" means you probaly got the Golden Jade already, right?
That item is needed to be brought to a certain place in the desert while in the right form.
If you have not found the item yet, try looking around the abandoned laboratory.
I hope this helps, if not feel free to ask more!
If you want the solution:
Visiting the Dragon Sanctuary in the Desert with it can trigger some new event when you are visiting that place in Salamander Form.