Clue in the Castle Tower

Samantha and Nellie are in England for the first time, vacationing with Grandmary and the Admiral. They are excited to visit an English knight who lives in an ancient manor house, next to a castle that's rumored to be haunted. But the visit turns spooky when the girls see odd and eerie lights in the castle tower at night . . . and learn that valuable books are disappearing from the manor's library. Can the girls find out who-or what-is behind the strange happenings? Includes a "Looking Back" essay about Americans traveling abroad at the turn of the last century.