A holiday in Cornwall turns into an unexpected adventure when Jo, Sarah and Andrew Lawrence discover an old manuscript containing a strange riddle. The Lawrences join forces with newly-found Cornish friends to try and solve the riddle. But they soon realise that there are enemies about, and they must fight to outwit the opposition, as the treasure hunt hots up. Clues lead them through a chain of Cornish villages; standing stones; amazing coastlines and beaches. But the race is on to reach the treasure first...if they can only solve the riddle and outwit their enemies...