The film follows Allan Karlsson who, on his 100th birthday, decides he has to do more than sitting in the retirement house and waiting for death, climbs out of his window and disappears. He starts his extraordinary journey which for anyone else it would be a lifetime adventure, engaging a suitcase full of cash, some unhappy criminals, a friendly hot-dog stand operator, and an elephant. It cannot be more excited as along the story progress, it reveals that this adventure is not Allan's first. For a century he's turned the world upside down, and now he is doing it again!