Agatha Raisin and the Haunted House

Agatha Raisin and the Haunted House (Agatha Raisin Mysteries, No. 14) - Agatha is determined not to fall in love with her new neighbor, Paul Chatterton.  However, when an elderly woman, Mrs. Witherspoon complains that her home is haunted, Paul convinces Agatha to help him investigate.  Agatha is convinced that there is a secret passage in the house and that the haunting and subsequent death of Mrs. Witherspoon is related to the Civil War in England.