Summoned by the Queen of England to save the world once again, trusty kid spy Mac B. navigates secret tunnels beneath the Berlin Wall to retrieve cheat codes from an adversarial scientist only to find himself trapped in East Germany.

"My name is Mac Barnett. I'm an author. But before I was an author, I was a kid. And when I was a kid, I was a spy. This is a story of stolen violins. It's got mummies, museums, sandwiches, hostages, and a dangerous showdown with the Russian Red Army Choir. Open this book to find out more about my adventures. But beware--this mission is top secret and very dangerous!"--