The British actress Andrea Riseborough is one of those metamorphic changelings so different from film to film, role to role, that few people realize she’s even out there. In the past 12 months alone, she’s played Stalin’s daughter in “The Death of Stalin,” Billie Jean King’s lover in “The Battle of the Sexes,” and the creepy murderess in the “Crocodile” episode of “Black Mirror.” She’s a stroppy teen punk in one of her first films, the prize-winning 2008 short “Love You More” ( warning — NSFW), and has six projects in the pipeline for this year and next. And you can’t probably call her face to mind, can you?
The keys are her eyes, cobalt blue and sometimes soft but more often bleak and determined. In “Nancy,” Christina Choe’s writing-directing debut and one of Riseborough’s too-few starring vehicles (the actress produced it, too), those eyes are landlocked in an impassive face, framed by a mop of frowsy black hair that doesn’t quite look like it belongs to her. Living in the middle of a New York State nowhere, with an ailing and abusive mother (Ann Dowd, of course), Nancy is one of those meek, unsettled souls with something raging inside her. Even she may not know what.
Shot and paced in a mood of downer realism, the film follows Nancy as she gets one more rejection notice for her short stories, tells lies at her temp job about a North Korean vacation she didn’t take (who goes to North Korea for vacation?), and bonds with a grieving father (John Leguizamo) she has met online by pretending to be pregnant. Is she a scam artist, a psycho, a woman derailed by loneliness? All of the above? At times, it’s unclear whether “Nancy” is withholding information out of suspense or narrative uncertainty.
Eventually this search for identity finds a place to land: a news item about a girl gone missing 30 years earlier and the parents who’ve never stopped looking for her. The photo looks like it could have been Nancy (in fact it’s a picture of the young Riseborough), as does an artist’s rendering of the girl as an adult. Questions linger in Nancy’s mind about her own beginnings — a birth certificate is notably nowhere to be found — and she reaches out to the bereft old couple, Ellen (J. Smith-Cameron) and Leo (Steve Buscemi). Which is where the movie truly begins.
So is she or isn’t she? That question becomes the primal mystery of “Nancy,” and it’s a mark of Choe’s skill that she leads the audience into a state of hoping Nancy turns out to be the missing daughter and equally dreading it. Buscemi is touching in a change-of-pace buttoned-down role — Leo is a psychologist and his wife a professor of literature; the class difference between them and the no-collar Nancy is one of the unstated hurdles separating them — but the film also serves as a rare movie showcase for Smith-Cameron, better known for a near-legendary New York stage career and TV’s “Rectify” (as well as for being married to writer-director Kenneth Lonergan).
The delicate dance between Ellen, desperate to believe this woman is her daughter, and Nancy, who doesn’t let us know what she believes, is scary and strange and ultimately very moving. (Leo, the movie’s necessary skeptic, has arranged for DNA tests, and the several days’ wait for the results becomes the stage for the final half of the movie.) Riseborough’s character gives nothing away; we realize Nancy has next to no social skills and that her primary emotional attachment is to her cat, Paul, who has accompanied her on the trip and who bedevils the allergy-prone Leo.
That waiting is the meat of “Nancy” — the handful of days when Nancy simultaneously is and isn’t Ellen and Leo’s long-lost child. (Maybe the cat really belongs to Schrodinger.) Once the matter is resolved, the movie deflates and doesn’t really have anywhere to go; in that period of taut unknowingness, a relationship comes to life that is all things at once: mother to daughter, lost soul to lost soul, friend to friend. “Nancy” is an eccentric, pungent gift of a film about a woman without identity played by an actress without persona.
Written and directed by Christina Choe. Starring Andrea Riseborough, J. Smith Cameron, Steve Buscemi, Ann Dowd. At Kendall Square. 87 minutes. Unrated (as PG-13: adult themes, clammy existential disquiet)Ty Burr can be reached at email@example.comFollow him on Twitter @tyburr.Follow him on Twitter @tyburr.. Follow him on Twitter @tyburr.