Two brothers in their seventies, Pa and Moe, have lived together all their lives in a little house in the country, the only interruption being when Pa made a weekend trip to Småland on his moped during the second World War. The past returns when his adult son dating from his Swedish visit, Konrad, comes to live with them after his mother has fallen ill. Soon Moe is about to discover that three is indeed a crowd...
A foreign criminal gang makes a large-scale bank coup. The suspicion falls on the Olsen Gang. They escape, take up the hunt for the real criminals and thus it all starts. The police are looking for the Olsen Gang, and they are looking for the real criminals.
Egon Olsen is commissioned to help a baron with an insurance fraud. As the dividend can finance Basse's wedding, even Valborg accepts the plans.
