Girls in Chains (1943) on Netflix

Plot summary

Helen Martin teaches school, but her sister Jean's marriage to Johnny Moon costs Helen her position. Moon is a racketeer who controls the city's politicians and secretly runs a reformatory for women, and he has ruined many lives, Helen's and Jean's among them. Frank Donovan, a political reformer, asks Helen to take a place inside that reformatory as a teacher and to look for proof of how Moon treats the women held there. Helen wants to give the inmates a chance at a different life after they leave. The supervisor answers to Moon, takes money from the facility's budget for himself, and the matrons set the girls to laundry work.