In Copenhagen in 1933, Maren (Emilie Kroyer Koppel) is a rebellious teenager, who dances to jazz music at nightclubs and parties until late to escape the drudgery and squalor of her home life.
After neighbours complain about her behaviour, Child Services comes to interview her mother, and subsequently decides to place her in a home for delinquent girls.
He believes she is unable to answer them, and also sexually promiscuous, and diagnoses her as mildly mentally deficient, recommending she be placed in a home on the island of Sprogø.
Once she realises she has thereby condemned herself to a long stay on the island and its strict rules, Draconian punishment, isolation, and menial work, she begs to be interviewed again, but is refused.
One day, workmen visit the island to carry out repairs, and are forced to stay overnight due to heavy seas and bad weather.