Sitting quietly in his room in an old people's home, Allan Karlsson is waiting for a party he doesn't want to begin. His one-hundredth birthday party to be precise. The Mayor will be there. The press will be there. But, as it turns out, Allan will not . . .

Escaping (in his slippers) through his bedroom window, into the flowerbed, Allan makes his getaway. And so begins his picaresque and unlikely journey involving criminals, several murders, a suitcase full of cash, and incompetent police. As his escapades unfold, Allan's earlier life is revealed. A life in which - remarkably - he played a key role behind the scenes in some of the momentous events of the twentieth century.