Leo Woodall is the first to admit that he doesn’t know a lot about math.
In the new mini-series “Prime Target,” streaming on Apple TV+, the 28-year-old British actor stars as Edward Brooks, a graduate student in mathematics at Cambridge whose visionary work places him in the cross hairs of a shadowy government agency. When he isn’t on the run, Brooks spends much of his time jotting down arcane equations and scrawling algebra on chalkboards — “not a single lick of which did I understand,” Woodall admitted with a laugh.
“I had some maths lessons, but it was unsuccessful,” he added. “So I just decided to memorize it all and write it as quickly as I could. It was a deeply stressful process.”
“Prime Target” is a math thriller in the vein of “A Beautiful Mind,” Ron Howard’s Oscar best picture winner about the mathematician John Forbes Nash Jr. and his work in Cold War-era cryptography. Brooks’s work is purely hypothetical and concerns patterns in prime numbers, but as he goes deeper, he finds himself within reach of a key that can unlock every digital password in the world.
“Right now, math nerds are probably the most dangerous people on the planet,” Taylah, a National Security Agency agent played by Quintessa Swindell, explains to a colleague.
The series creator Steve Thompson should know. A playwright and screenwriter best known for his work on “Doctor Who” and “Sherlock” for the BBC, Thompson is a self-described math nerd who taught mathematics at a London high school in the 1980s and ’90s. “Prime Target,” he said, was a longtime passion project that he had been thinking about since those days.
In 1999, the writer Simon Singh gave a lecture at Thompson’s school on “The Code Book,” his study of the history of cryptography. Thompson was fascinated. “He had explained that in modern cryptography, everything is based on prime numbers, and that if anybody ever solved it, we’d all be in terrible trouble,” Thompson said. “At the back of the classroom, listening to him talk, was where the idea started to percolate.”
Nearly 20 years later, in 2017, the producer Ed Rubin asked Thompson what topic he would most like to write about if given a blank slate. “I want to write a thriller with a mathematical angle,” Thompson recalled saying. Rubin was intrigued, and they began to develop what eventually became “Prime Target.”
The series is directed by Brady Hood, who previously helmed Steven Knight’s 2023 adaptation of “Great Expectations” for the BBC and Hulu. Hood said that he wanted to avoid the clichés of the traditional math movie, “like the token superimposition of numbers on the screen,” and instead leaned into a thriller angle as Brooks becomes an enemy of the deep state and has to evade a dragnet of surveillance.
Hood added that he was inspired by the acclaimed “paranoid thrillers” of the 1970s, such as Francis Ford Coppola’s “The Conversation” and Alan Pakula’s “The Parallax View,” and used long lenses and distorted sound to suggest an air of unease.
“Part of the reason I wanted to do this job was my love of the Pakula films and those ’70s thrillers,” Hood said. “We’re contemporizing the world of the conspiracy thriller, but it’s also harking back to that as a homage just a bit.”
Woodall said that Hood suggested he watch films like “The Parallax View” and “Tinker, Tailor, Soldier, Spy” as homework for the role, which got him excited for the prospect of espionage action. “I was just waiting for the moment when they told me that I get to beat up some bad guys, but it never came,” he said.
Thompson said he knew that he didn’t want his thriller to get too bogged down by the numbers and wanted the show to still be accessible to viewers for whom arithmetic feels as arcane as Ancient Greek. At the same time, he said he was proud of the actual math that appears onscreen — all of it double-checked and corroborated by “a very large team of mathematicians,” and ready for any eagle-eyed nerds in the audience to scrutinize and pick apart.
Swindell plays the N.S.A. agent Taylah as a kind of bureaucratic computer hacker, and though Swindell doesn’t handle much math in the show, the actor spent some time with a surveillance consultant, and reached out to an old friend, “a computer guy,” for advice on the role, Swindell said. “I asked him, ‘Do you cover up the camera on your computer? Is that something my character should do in the series?’” Swindell recalled. “He said no, and I realized that my awareness of how all of this works is really bad.”
In a joint interview, Woodall jumped in with a grin: “We’re both sort of faking it until we make it here.”
Thompson said that Woodall, especially, deserves praise for the quality of his faking. “He spends a lot of the show writing reams and reams of mathematics incredibly fluently, and it’s very complex stuff that he writes,” Thompson said.
In a scene toward the end of the series, Brooks writes out a formula for finding prime numbers that takes up about six by three feet of wall space and which Woodall had to write out by hand, from memory. “We rolled the cameras for about 20 minutes as he was writing it, and the guy nailed it,” Hood said. “He absolutely nailed it.”
Woodall, however, remembered it somewhat differently. “I think I got one letter wrong, and one of the consultants came in and said, ‘That’s good, but, hmm …’,” he recalled. “I was so proud of what I’d just done, and he knew I’d screwed it all up.”
“Oh, come on!” Hood exclaimed when he heard Woodall’s retelling. “Give the boy a chance!”
