Mac B. is back...and this time, a new enemy is after the Crown Jewels!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!  The action in this new adventure is nonstop, as Mac travels to an ancient Irish castle to solve the mystery. There, he encounte