Nikyatu Jusu’s film Nanny carries a premise full of potential: Aisha (Anna Diop) is a former teacher from Senegal hired as a nanny for the daughter of Amy (Michelle Monaghan) and Adam (Morgan Spector), a wealthy white couple in New York City. We gather from the jump that this arrangement might not work out so well – Aisha needs to be paid in cash in order to send it back home to her son, and the tightly wound Amy doesn’t always remember to do so. And Adam may or may not be trustworthy himself.

Nanny brims with tension, which Jusu keeps teasing will tip over into the realm of a supernatural thriller. Water imagery keeps flooding the screen. Aisha is continually haunted by nightmares, both in sleep and while awake. The film wants to be a metaphor for the struggles of the immigrant, for the underprivileged and working parent.

But the tension never reaches a full boil. Nanny wants to be a thriller but the only punches it pulls – including an unforgiveable one that comes late in the film – feel unearned. One can sympathize with Aisha’s plight without the addition of Jusu’s heightened strokes: the real world is more than frightening enough.