The Hidden Passage

Roger, Matthew, Susan and Rachael are four children who excitedly make their way home from their school in London to their parents' new home in Wales by the sea to spend their summer holidays. But cliffs, hills, caves and the water itself are all dangers which encourage the children to take further and further risks. Before long, they become lost in a cave and stumble upon a mystery which becomes more and more baffling with new and terrifying dangers round every turn.