In their first adventure, the super-sleuths are on the trail of some strange clues. Jack hears strange noises outside his house and discovers a spooky old caravan. The Secret Seven are determined to find out what is going on.
The Secret Seven have a brand new meeting place but somebody else has been using it too. How dare they? Whoever it is is going there at night, and the gang are going to put a stop to it! They are determined to catch the cheeky intruder, whatever it takes.