Penny Pepper helps Scotland Yard Grandma won a trip to London in a contest. For five people. And Penny and her friends are allowed to come along. But shortly after their arrival, Grandma's precious gold chain disappears, even though tour guide Emily had warned them so forcefully about the pickpockets. And it doesn't stop at this one theft. After visiting Big Ben, a camera, a pair of sunglasses and a chunk of money are missing. Not an easy case for Penny and company, because there are plenty of suspects.