The Crown Jewels are in danger... again! When the jewels go missing from inside a locked room, Mac's spy skills are put to the test. How did the thief break in? Where did the jewels go? And will Mac be able to solve this locked room mystery before the thief escapes? This mystery isn't just a whodunit... it's a howdunit!

Don't miss the installment of this totally smart and sidesplittingly funny New York Times bestselling series, Mac B., Kid Spy.