We were dangerous

In 1954 New Zealand, Nellie and Daisy attempt to escape an institution for delinquent girls, but they are caught and it triggers a relocation to a facility on a remote island. The duo become a trio as well-to-do Lou joins them, and life on the island takes shape under the command of the devout Matron. The trio rail against the system, dubious of the benevolence of the bible and taking refuge in their blossoming friendship.