After a weekend of dancing and camping on a recreation island near the city, a young factory worker decides to stay and cut work for a day. Walking around the now deserted island, he meets a beautiful woman camping alone and sunbathing in the nude on the beach. A hot romance flares up between the worker and the more upper-class married lady, lasting through the light-filled nights of the whole summer week until the woman's much older husband returns to the island the next weekend.

Gunvor Sandkvist
as Siiri Forss

Matti Oravisto
as Usko Siltanen

Toivo Mäkelä
as Bertel Forss

Paavo Hukkinen
as Usko's 1st Pal

Kauko Laurikainen
as Usko's 2nd Pal

Juhani Kumpulainen
as Agitator

Kaarlo Saarnio
as Usher

Leo Jokela
as Usko's 3rd Pal

Matti Kassila
as Narrator (voice) (uncredited)

Maija Autio
as (uncredited)