Moments before her death, Mrs. Treverton dictates a secret to her maid. Fifteen years later her daughter Rosamond Treverton returns to her birthplace- Porthgenna Tower on the remote Cornish coast. When the strange and seemingly disturbed Mrs. Jazeph warns her not to enter the Myrtle Room, the strong-minded and ingenious Rosamond is intrigued. But her determined detective work uncovers shocking and unsettling truths beyond all expectation.
