Fourteen-year-old twins, Lucy and Archie Scott, can't wait to visit their Uncle Jacob in Cornwall and arriving at Gull Cottage, they're not disappointed. Greeted by their uncle, his eighteen-year-old nephew Troy, and Kristo, a high-tech, electronic Great White shark, the twins know they're in for an action-packed summer.
There's just one problem: the Riddle brothers. Len and Joe, known thieves and archenemies of the Scott family, own the local scrap yard. With dreams of caravan parks and tourists' wallets, the Riddles have their eyes on Gull Cottage, intending to demolish the house for their own moneymaking goals. With the Stinger (a mini submarine) on their side, they set about their goals to outsmart the Scotts.
A storm is brewing. Can the Scotts solve the puzzle the Riddles present? And what other dangers lurk beneath the waves?
