Although Netflix has a reputation as an escapist clearinghouse, the streaming service isn’t averse to the occasional tough sit. The Austrian film “Joy” – the title refers both to the main character’s name and the precise opposite of the film’s mood – follows a Nigerian woman who is trafficked illegally to Austria, where she works as a prostitute and sends money home. The film opens with a girl participating in a ceremony with a Juju priest who, we later learn, is essentially ensnaring her – making her think that disobedience in Europe will bring bad luck. In the first of several intelligently uninflected leaps in time or geography, the director, Sudabeh Mortezai, jumps from this scene in Nigeria to a title card and then to Austria. By now, Joy, who has undergone such a ritual, is an experienced streetwalker overseeing a newcomer, Precious. The cycle is difficult to break: Joy and Precious’s madam, who collects their debts over a period of years, pits her stable of women against one another.