Fair Salvage
An ancient and mysterious race revisits Freeport for the first time in two centuries.
The adventure culminates in an encounter with a strange new race. The adventure from that point is up to the GM, but could include the PCs facilitating diplomatic relations, negotiating recovery of ancient artifacts without bloodshed, or working with an underground rebellion to rid Freeport of the Strangers. It's probably not an adventure to take on as a beginning GM.
NOTE: The Tales of Freeport that contains this adventure is NOT one of the versions currently available in the Green Ronin store. Those contain short stories. This is an older item that appears to no longer be available from Green Ronin. It is possible that the adventures within it have been included in other products since then. But I have linked to the original product on DriveThru RPG.