Like the struggling immigrant on the verge of a better life in America, viewers of Nanny are forever perched on the edge of the couch, waiting for the film to live up to its promise.

There are fleeting moments when Nikyatu Jusu’s much-hyped feature debut, which won the Grand Jury Prize at this year’s Sundance festival, fulfils its classification as a horror film. Most of these have to do with water, used here as a metaphor for the heroine’s journey.

Nanny is being streamed on Amazon Prime Video. The English-language movie’s chief draw is a star-making turn by Anna Diop in the lead role.

Aisha (Diop) has migrated from Dakar in Senegal to New York City, where she finds work as a nanny for a wealthy couple’s only daughter. Aisha and Rose (Sinqua Walls) bond instantly, with Rose particularly warming to Aisha’s spicy Senegalese cooking. The mother, Amy (Michelle Monaghan), who works in a high-pressure job, and the father Adam (Morgan Spector), a photographer, are barely around.

Aisha is deeply missing her own son, who is back in Dakar. She puts in extra hours to be able to pay for him to travel to America. But then the unsettling visions begin.

Nanny, which is being streamed on Amazon Prime Video, has the unmistakable feel of a short film extended into a full-length feature. The scares are mild and in short supply over a narrative that burns far too slowly.

Gorgeous visuals by cinematographer Rina Yang and Jusu’s skill at setting up scenes keep Nanny afloat. Rather than a socially conscious fable about displacement, the 97-minute movie is far more engaging as a character study of a doughty survivor of trauma trying to make it in an alien land.

Anna Diop, who is present in nearly every frame, single-handedly delivers emotional payoff sought by Jusu. Although Diop sometimes appears a bit too polished to be entirely convincing as a struggling migrant, her fiercely compelling presence makes even weak scenes appear special.

Nanny (2022).