A group of friends travel to a cabin in the Norwegian forest. It's a rumour that at night a crazy man can be heard screaming at a lake nearby the cabin.
The Olsen Gang realizes that cash is obsolete with the current inflation rate, and plans a coup for property and bonds. They make a fake company and tries to buy Oslo's biggest shopping mall, Steen and Strøm.
Fifteen years after they last saw each other, Benny, Valborg and Dynamitt-Harry discovers that Egon Olsen is out of prison and living in a retirement home. Olsenbanden is reunited, and Egon has a plan.
