Curse of Strahd
A House in the village of Barovia. The group found the remains of Rose & Thorn, two children who had been sealed in a room & starved to death. The house had an alter in the basement which appeared to be used by a cult to make sacrifices. The cult awoke a Shambling Mound which attacked the party before they ran away.
A letter was found here, written to the cult from Strahd Von Zarovich.