The Mystery Series: The Mystery of Holly Lane: Book 11  Enid Blyton

The Find-Outers have no mystery to solve, so Larry disguises himself as a window cleaner. But Larry, Fatty, Daisy, Pip and Bets soon discover that money has been stolen from the bungalow Larry was cleaning – and a few days later, all the furniture is gone too!

The Find-Outers are on the case to discover who the thief is…