Mac B. is on a secret mission to retrieve a stolen, priceless piece of history in this totally true kid spy adventure! England is in trouble! A priceless violin has been stolen, and there's only one person who can help: Mac B., kid spy. Mac's adventure takes him on a top-secret museum night watch, zip-lining in Italy with his trusty corgi sidekick, and on an undercover mission in the heart of enemy territory. But when he ends up as a captured prisoner, is the mission lost for good?