It is 50 years ago, the first film about the Olsen gang came up in Danish cinemas, and TV 2 celebrates the anniversary with a new entertaining TV documentary in two parts. The film series and its beloved characters are described with selected film clips and through a mix of old archive footage and new interviews. Come i.a. with behind the camera for the recordings of 'The Olsen gang's last exploits' from 1974, where Ove Sprogøe had almost lost his life. In addition, composer Bent Fabricius-Bjerre tells how the famous music came to be. 'The Olsen gang forever' is a tribute to the Olsen gang, and the series' cinematic universe, which has become Danish public property and part of our common cultural heritage.