A woman is found murdered in a closed amusement park. A young couple who happen to be there at the same time become, without their knowledge, suspects for the murder. They are chased by a large number of police but only Martin Beck believes them to be innocent.

Gösta Ekman
as Martin Beck

Kjell Bergqvist
as Lennart Kollberg

Rolf Lassgård
as Gunvald Larsson

Johan Widerberg
as Kasper

Marie-Thérèse Sarrazin
as Mårds kvinna

Tomas Norström
as Herrgott Nöjd

Anica Dobra
as Kia

Heinz Hoenig
as Kapten Mård

Agneta Ekmanner
as Greta Hjelm

Stig Engström
as Kaj Sundström