HBO

Nightingale poses a challenge to its viewers from its opening scene on. Protagonist Peter Snowden (David Oyelowo) has done a terrible thing—only hints of the aftermath can be glimpsed on screen—and the audience is trapped in his house with him. The film, which premieres on HBO Friday, is an audacious one-man show—a series of deluded, sometimes charming, often tragic, occasionally frightening monologues delivered by a troubled veteran clearly in the midst of a dissociative crisis. Peter works in a menial job and lives with his mother at home, where Nightingale is entirely set, but, as he repeatedly states, his “circumstances have changed” in horrifying fashion.

It's quickly apparent that Nightingale is going to be a claustrophobic experience, with Oyelowo the only person to appear on-screen for its feature-length running time. To the British actor, that made the script stand out all the more—it was written by a total unknown, Frederick Mensch, uploaded to the unproduced-script site The Black List, and quickly discovered there by the producer Josh Weinstock, who helped shepherd it to the screen. In an interview, Oyelowo said he was floored by the script's unusual format and the immediate revelation of what could have been its biggest plot twist.

“Frederick Mensch made the extraordinary choice of revealing what Peter has done from the first scene,” he said. “That's the point at which potentially the audience can go, ‘Okay, well I can't hang around this guy for an hour and a half.’ But within the writing, even as Peter is behaving badly and telling lies and in denial, there's a humanity that bleeds through, and an empathy.”

Nightingale's strongest achievement is finding that humanity in a character who could very easily come off as a psychotic caricature. The sources of Peter's demons are easy to chart: an overbearing mother, a traumatic experience in the military, and a decades-long struggle with his sexuality that plays out as an obsessive fixation on a fellow soldier. The central plot of Nightingale sees the newly liberated Peter trying to invite his friend over for dinner while batting away phone calls from his mother's concerned church friends and relatives and remodeling her home in a manic fashion. He talks on the phone, talks to himself, and most of all talks to an invisible audience that presumably exists online, speaking into a camera and “welcoming” comments that never come. Peter is at times flamboyant, and at other times stiff and fussy, but Oyelowo captures his humorous edges without ever crossing into more cartoonish territory.

“I wanted him to feel rooted in reality,” Oyelowo said. “There are people like Peter out there, having spoken to a psychiatrist. He’s not a psychopath, but he’s someone who suffers from dissociative identity disorder, whereby he has splintered himself into various variations born out of trauma in order to deal with his day.”

Nightingale’s main problem derives from the fact that its biggest strength—the unusual presentation—doesn’t allow a lot of room for plot development. Within 20 minutes, one can figure out everything that’s happening with Peter and the basics of his tortured past, leaving the rest of the film over to the slow build of tension. Will another character enter, or at least try to enter, the house at any point? Are Peter’s confessional monologues to camera being picked up by anyone in the outside world? Ambiguity largely prevails, so it's entirely on Oyelowo to hold the audience's interest after a certain point.

“It was a challenge that I relished, really. Whether you’re a great ginormous movie star, or you're looking to do good work, when a script like this comes along, it tests your mettle,” Oyelowo said. “[Reading the script], you say, ‘Okay, if I'm going to fail, let me fail forward,’ and that’s how I felt. Even if it doesn’t work, I absolutely knew that I would be a better actor for having stepped into something that felt very exposing and terrifying. We put something unique out to the world, that is thought-provoking and challenging, so I decided to take the jump from that point of view.”

Oyelowo had been doing extraordinary work on stage and screen for years before his 2014 breakthrough playing Martin Luther King Jr. in Ava DuVernay's Selma, a performance that feels a world apart from Peter. To hear him tell it, that was a somewhat deliberate choice. “It’s such a blessing that Nightingale is coming out after Selma, which was a pretty unique experience in and of itself, but one that I don't necessarily want to be solely associated with,” he said. “I want to do lots of different things, and I think the more you make changes, the more the audience will hopefully be interested in what you're doing next.”

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