The second book in the adventure series by the most beloved children's author worldwide. Jack, Lucy-Ann, Philip, Dinah, and their cute and talkative parrot, Kiki, start their vacation at Spring Cottage on the slope of Castle Hill. When Jack notices bright signals from a distant tower, he decides to explore the hidden rooms and dark underground passages of the ruined castle. What mystery lies in these paths? Why does everyone believe the castle is haunted? Are you ready for... adventure?