Gundren the Dwarf has been taken captive by some goblins, and taken to a castle. The castle's location is currently unknown, but is known as CragmawCastle.
Located north east, according to Fiert the Goblin
he has been taken to the Black Spider, they were looking for "the dwarf who holds the map".
The goblin problem in the area is bigger than previously thought. 500gp reward for taking down the main force at Cragmaw Castle.
People in Phandalin tell the group about a wandering Druid, named Reidoth/Reidolph. He might know about the location of Cragmaw Castle, and is currently located at Thunder tree