This is one of the opening options for the quest "The Goblin Problem".
"The office of the mayor in the Castle of the Moon is dimly-lit, warm, and filled with books. On either side of the long room are shelf after shelf of tomes, each chained lightly to the copper bar beneath them. At the far end of the chamber, beneath the large round window, is the dark wood desk of the mayor herself, who sits surveying you with a furled brow. With a quiet sigh, she gestures you to sit."
Bairtha Moondaughter will thank them for their assistance with Fernall Sonome, or for their interest if they found the notice, and will explain that tribes of goblins have been preying on her people for decades: they steal their goods, destroy their tools, and will attack vulnerable travellers on the road.
If Fernall Sonome is right, and they have found the legendary ruin of Lord Gladsvain, this is the next step in a conflict that will only end in disaster. If the players go to the ruin and rout them, the town will pay them 200 gp.
A DC12 Wisdom (Insight) check on either Bairtha Moondaughter or Fernall Sonome will confirm that there is something that they are not telling the players - namely, the capture and then escape of Calla Darkearth - though they will both deny.
The players may then go to the place where Fernall Sonome was ambushed to investigate and find the Hall, or they may stay in town and gather more information. After their interview, Fernall Sonome will head over to the cathedral to be tended to by the Abbot. The players may accompany him.