On a Mission for Her Majesty (Flat Stanley's Worldwide Adventures, Bk. 14)

Stanley and his family receive an unexpected phone call from Scotland Yard. Stanley has been invited to London to help with a top-secret case. One of the crown jewels was stolen years ago. The Queen has long suspected Lady Laura, her distant cousin, of the theft, and Lady Laura will be in London to attend a formal ball at Buckingham Palace. If she has the jewel, this will be the perfect time to wear it. And that’s where Stanley comes in.

Stanley loves the idea of being a spy, even if being flat has nothing to do with his mission. Or so he thinks...