The Banshee's Tower (OSE)

Publisher's blurb:

The tower formerly known as Asher’s Redoubt served as a minor border fortress and occasional gaol. The tower helped secure a trade road and played host to caravans and couriers. Its captain, Per Yeren, was a popular commander and friend to the locals. During the war a decade ago known locally as the Outburst, the tower fell after a brief siege, and its garrison slaughtered. After the hostilities passed, the locals returned from hiding in the fens, buried what remains they could readily recover, and left the place alone, a haunted monument to its defenders and the war.