The UK's #1 bestselling children's author, David Walliams, is back with a thrilling historical adventure with life-or-death stakes—chock-full of Walliams's unmistakable humor and perfect for fans of Stuart Gibbs and Gordon Korman.

1940. BRITAIN IS AT WAR WITH NAZI GERMANY.

Eleven-year-old Eric practically lives at the London Zoo. And there's one animal in particular he loves to spend time with: Gertrude the gorilla.

But with German bombs raining over London, Eric realizes Gertrude is in terrible danger, and together with his Uncle Sid, a keeper at the zoo, the three go on the run. But while hiding out at the seaside, they uncover a top-secret Nazi plot...