'Spending their summer holidays at a caravan park on the coast, Luke and Jason find a heavily concealed and locked door. In their quest to discover what secrets may be hidden, they stumble upon others who also have an interest in the door and may be using it.Is the park owner also involved? Why is the door so well concealed? What lies beyond? Where does it lead? Their detective work leads them to some surprising discoveries and near disaster for Luke.The setting is a coastal caravan park in Victoria, Australia.The year is 1990 in a time where the internet and social media was not available to teenagers to communicate and plan their adventures.' (Publication summary)