After reading the screenplay for Eye in the Sky, a thrilling, minute-by-minute account of a fictional military operation featuring three remote-controlled drones - a Predator aircraft armed with laser-guided missiles and two tiny surveillance vehicles, one disguised as a hummingbird, the other a beetle - filmmaker Gavin Hood had a powerful reaction.
"Oh, my God," Hood recalls thinking. "Is this stuff real?"
The answer, as it turns out, is pretty much. If some of the technology, which sounds like the stuff of science fiction, isn't in use just yet, Hood says it's coming. "Not only is it just around the corner, but our film is very soon going to be out of date."
In Washington recently to promote his new film at a preview screening - at which viewers were treated to a demonstration of a miniature military drone called the Black Hornet - Hood acknowledged that there is a tension between the film's futuristic technology and its ripped-from-the-headlines verisimilitude.
Against a backdrop of high-tech gizmos, the story revolves around the hunt for a fugitive Englishwoman suspected of working with the East Africa-based al-Shabab militant group. Her character is based on real-life terrorism suspect Samantha Lewthwaite and actual Somali refugees who fled al-Shabab were cast as Kenyans in the film. Hood says he interviewed military intelligence officers and drone pilots for authenticity.
The story, by Guy Hibbert, jumps back and forth between an al-Shabab safe house in Nairobi, where a suicide bombing is in preparation, and an English military base. From that command post, a British intelligence officer, played by Helen Mirren, interacts with a constellation of far-flung intermediaries: two drone pilots in Nevada, ground troops in Kenya, image analysts in Hawaii and Cabinet-level observers in a London briefing room. Despite the film's preoccupation with military jargon and tech-speak, Hood insists he was not interested in telling a conventional war story.
The more important question, he says, is "How do we win the big fight?" That question has long intrigued the 52-year-old Hood, a Los Angeles-based South African who was drafted by his country's marines at age 17 and subsequently trained as a lawyer. Hood says his legal background fuelled his storytelling impulse, which has also produced the 2007 Rendition, a political drama about the extra-legal kidnapping and torture of terrorism suspects by the US government, and Enders Game, a 2013 sci-fi adventure about the morality of preemptive war.
"In a sense," Hood says, "all good drama is about people in conflict, and law is usually about people in conflict. I think the stories that I like to tell and find most interesting to watch are stories that prompt us to think, without clubbing us over the head."
Eye in the Sky has to do with the unintended victims of war. As Mirren's character is about to give the order to release a Hellfire missile, a child wanders into the blast radius. Although Eye in the Sky includes frank discussion of the value of one child's life as weighed against the 80 potential victims of a suicide bombing, Hood says the screenplay intentionally avoids characters with cavalier attitudes.
The Creech Air Force Base bunker where the film's drone operators (played by Aaron Paul and Phoebe Fox) work - and ultimately question their work - is, in some ways, the film's moral heart.
The point of the movie, Hood says, is not to argue for a single point of view, but to "generate a conversation" about the cost of war.
Hood worries that we may be winning the ground battle while losing the propaganda war. How many more terrorists are we creating, he wonders, when we inadvertently kill a child in the effort to stop a far worse calamity? In its essence, Hood compares Eye in the Sky to an elaborate version of the "trolley problem", a thought exercise in which a train operator must confront an ethical dilemma: redirect a runaway trolley from one track - where several people would be potentially be killed - to a second track, in which only one fatality would occur.
"As [philosopher and political theorist] Hannah Arendt said, whenever you choose the lesser of two evils, don't forget: You're still choosing evil," Hood says. "What I am definitely not a fan of is this simplistic idea of good versus evil." Hood argues that idea is reinforced by a lot of mainstream movies.
"Ever since Star Wars hijacked the hero's journey and said, 'The hero is good', we have to have an antagonist," he says, "all the screenwriting books started coming out, talking about 'Have a hero, have an antagonist'. But the hero's not always good. This is not true. This is not even human."
According to Hood, it was something of a surprise to step back and realise his last three films - Rendition, Ender's Game and Eye in the Sky - could all arguably be called anti-war movies. It's a surprise, he says, for two reasons: that message was never his intent and he isn't actually against war.
"One thing I am not is a pacifist," says the filmmaker, who defines the term as "someone who would say, 'I would never, ever pick up a weapon'."
These days, his passion for battle manifests itself in making movies that argue for complexity and questioning the nature of, but not the need for, fighting.
Who: Gavin Hood, director
What: Eye in the Sky
Where and when: At cinemas now