'Nanny' trailer promises both waking and nightmarish horror

The first trailer for psychological horror Nanny has arrived, finally giving the wider public a first look at one of the best films at the Sundance Film Festival this year.

Written and directed by Nikyatu Jusu, Nanny follows Aisha (Anna Diop), an undocumented Senegalese woman who recently emigrated to the U.S. Hired as a nanny...