Trixie Belden and The Mystery of the Emeralds (#14) - 1965
By Kathryn Kenny
After Trixie finds an old letter in her attic, she tries to solve a 100-year-old mystery She and the Bob-Whites go to Williamsburg, Virginia, to find an old plantation house - Rosewood Hall - that was the home to the Sunderland family during the Civil War. Rumor has it that a cursed emerald necklace is buried in a secret passageway there. But after all that time, Rosewood Hall is just a ruin. Is it too late for Trixie to find the missing emeralds?
What I like about this book is the fact that the trail of the mystery starts in Sleepyside and leads Trixie somewhere else. The mystery is well written and it has great scenes with a couple twists, and the suspense will keep you turning pages.