Tales of Gloomsdale #6: The Banshee of the Lighthouse

Rowan and his sister Lynne are visiting their father, who has gotten a job as the keeper of a lighthouse. As they explore the lighthouse, they realize why he's the first person to get the job in years. They keep hearing strange wails and discovering odd-looking stones that make them think of the story of the banshee that their father told him. And that's before they head down to the basement and discover the letters that tell them the fate of the old keeper and the banshee...