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 the case!;

Solve the mystery! 

Cover and inside illustrations are by the brilliant Tony Ross, illustrator of David Walliams's books. The story was first published in 1951. This edition features the classic text and comes with a Bonus Blyton s