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.
An unfaithful servant in the Norwegian Petroleum Directorate tries to sell top secret information to German industry leaders. Egon has a plan to earn money on the transaction himself.