For Aiden, Chloe, Ava and Josh, holidays at their grandparents' cottage mean wild beaches, no curfew, Bella the dog, and most of all - adventure! A picnic at a stately home takes a suspicious turn when the cousins discover a jewel heist unfolding around them. But how can they take down a gang of clever thieves when all they've got is their bikes and a very risky plan? By being braver, smarter, and sneakier than the villains they're chasing. . . Fleur Hitchcock is famous for her excellent "thrillers for beginners". This action-packed series takes 7+ readers on fantastic, realistic adventures. Cover illustration by Tom Clohosy Cole.