Set in Denmark in the here and now, The Quiet Girl centres around Kaspar Krone, a world-renowned circus clown with a deep love for the music of Johann Sebastian Bach, and an even deeper gambling debt. Wanted for tax evasion and on the verge of extradition, Krone is drafted into the service of a mysterious order of nuns who promise him reprieve from the international authorities in return for his help safeguarding a group of children with mystical abilities.

When one of the children goes missing a year later, Krone sets off to find the young girl and bring her back, making a shocking series of discoveries along the way about her identity and the true intentions of his young wards.