David Walliams Grandpa's Great Escape Book

Grandpa is Jack's favorite person in the world. It doesn't matter that he wears his slippers to the supermarket, serves Spam a la Custard for dinner, and often doesn't remember Jack's name. But then Grandpa starts to believe he's back in World War II, when he was a Spitfire fighter pilot, and he's sent to live in an old folk's home run by the sinister Matron Swine. Now it's up to Jack to help Grandpa plot a daring escape!