The story follows Allan Karlsson who, on his 100th birthday, decides there is more to life than waiting for death in a retirement home, climbs out of his window and disappears. What follows is an extraordinary journey, involving, among other surprises, a suitcase stuffed with cash, some unpleasant criminals, a friendly hot-dog stand operator, and an elephant. For anyone else it would be the adventure of a lifetime, but as the story progresses it transpires that Allan has a larger-than-life backstory: From Stalin to Reagan, not only has he witnessed some of the most important events of the Twentieth Century, but he has actually played a key role in them, albeit an accidental one.