Gregor and Sunniva arrive in Saltmarsh on an early summer afternoon of year 2632. They have heard that there are old ruins in and under the town, and are interested in investigating. If they ask around at various taverns, the market, etc... they learn that the Old Keep, the Temple of Centarius and the nearby tower are all quite old, at least 2nd Empire era.

They may (DC 15 Gather Info) learn that there are tunnels under all three, which could possibly reach out further into town.

If they ask who uses the tunnels, or try to find out who might know of an entrance, they should hear (DC 10) that there are smugglers active in the area, but nobody knows if they use the tunnels, and they may also hear that the tunnels once reached outside town (DC 15). They also may hear that the town's sewers once connected to the tunnels (DC 20) but have been sealed off since. They may also be told that either the sewerman's guild or the mason's guild might have maps of the tunnels.