Good Old Secret Seven: Book 12 by Enid Blyton
The Secret Seven are siblings Peter and Janet, and Jack, Barbara, Pam, Colin and George. Together they are The Secret Seven - ready to solve any mystery, any time - in Enid Blyton's classic series of 15 mystery novels.
In book twelve, there are strange happenings indeed at Torling Castle! Someone is hiding out in the ruined tower, making the resident jackdaws very unsettled.
Who is it, and what do they want? The Secret Seven are on it.
First published in 1960, this edition features the original text and artwork.