Return of the Gulls

Return of the Gulls, the first novel of the trilogy that introduces paranormal sleuths, Stacey Christian and Peter Mansfield.
In Return of the Gulls Stacey Christian unexpectedly runs into her ex-boyfriend, Peter Mansfield, while touring Ireland. They join forces to help solve the puzzles surrounding Lady Katherine O'Flannery, Peter's formidable great-aunt.
Finding herself implacably installed in Katherine's eerie castle, referred to by the locals as Faoilenn Màrrach, or Gull Castle, Stacey quickly becomes obsessed with the castle's disturbing legends - legends of suicide, desertion, embezzlement and revenge culminating in dark mysteries and ghostly hauntings.
Skepticism quickly turns to incredulity and finally terror as Stacey and Peter come face to face with a reality that neither could ever have imagined.