Allan Karlsson, who’s about to celebrate his 100th birthday in a retirement home, makes an unexpected escape: he climbs out the window in his slippers and embarks on a wild, absurd adventure.
 
He soon becomes entangled with criminals, a suitcase full of money, several murders, and very bumbling police.
 
Along the way, flashbacks reveal his surprisingly eventful life: Allan had a hand (in very strange ways) in some of the biggest historical moments of the 20th century.