A spooky old house, a historical mystery, an underground mine, and a rising tide—the stage is set for an exciting adventure in the tradition of Enid Blyton and Arthur Ransome
"Come round here!" called David. "We've found something."
"I'm showing them." Andrea pushed him aside. "It's my cave!" She lowered herself into the hole. Her head disappeared, and a moment later they heard her voice, faint and slightly hollow. "Come on!"
When Martin goes exploring under the cliffs with his friends David and Andrea and his sister Kitty, they find every kid's dream: a network of tunnels running under the park, with a secret exit under a mysterious ruined house. It's a great place for adventures, as long as their parents don't find out and forbid them to go there. As Kitty learns more about the old house, she begins to suspect that it is hiding something else, something very important to the ancient lady who once lived there—but as usual no one will listen to her. Martin wants to play out the fantasy adventure games he loves, David wants to forget about growing up for a while, and Andrea—well, Andrea will do anything as long as she doesn’t have to obey the rules. But David also wants to help his mother and grandfather in their fight to save the "Haunted House" from demolition, and it seems that the old lady's secret just might be the key. Are they imagining things, or are they being watched by someone who wants to see just what they are going to find in the old house?