PRISON GIRL follows Ayaka, a bored housewife, trapped in a loveless and pointless marriage. Her imagination, on the other hand, is vibrant. Ayaka has been experiencing the same dream since she was a teenager. The dream is of her in prison, repeatedly getting molested by the prison guards and warden. The line between fantasy and reality increasingly gets blurred, as Ayaka struggles to make sense of her vivid prison assaults and her deteriorating marriage.