The Clue of the Whistling Bagpipes
Carolyn Keene
 Nancy is warned not to go to Scotland, but she ignores the warning. She and her friends, Bess and George visit Nancy's great-grandmother at an estate in the Scottish Highlands. The Drew family's heirloom, a set of bagpipes is missing, and Nancy is determined to find it. While there, Nancy becomes involved in the mystery of missing flocks of sheep and a mysterious bagpiper has been spotted. Clues leading to a discovery in an old caste and a prehistoric fortress lead to the mystery's solution.