Virginia Hall’s story is unbelievable, even by Hollywood standards. But as cinematic as the covert American agent’s life was, she’d never been portrayed on film until Sarah Megan Thomas came along. A Call to Spy, the new feature from the Main Line-born writer/producer/actress, interweaves the adventures of Hall and other intrepid women whose talents and sacrifices were crucial to Allied espionage efforts during World War II.

A Haverford native, Thomas, 41, participated in theater at the Shipley School, but sports — cross-country, basketball, crew — were a bigger deal. Though she rowed as an undergrad at Williams College, acting became her primary focus, culminating with graduate studies overseas at Drama Studio London. A move to New York to pursue on-screen and off-Broadway jobs followed.

In 2012, Thomas orchestrated her own big break, drawing from her Schuylkill sculler past to write, produce, and star in Backwards, a rowing-centered romance with James Van Der Beek. For Equity, also filmed here, Thomas logged story and producer credits in addition to co-starring alongside Breaking Bad’s Anna Gunn. Praised for its assertive, female-first take on the traditionally man-heavy financial thriller, the Sundance selection was acquired by Sony Pictures Classics in 2016.

Investment in both the artistic and financial sides of the business has shaped Thomas' approach to new projects. “I always start with the genre, one I think is commercial and that audiences love,” she says. “Then I look at the female angle — which often means stories we haven’t seen before.”

In the leadup to penning A Call to Spy, which she’ll introduce at a Philadelphia Film Society drive-in screening tonight at the Navy Yard, Thomas immersed herself in researching the female operatives recruited by the UK’s Special Operations Executive (SOE) at the outset of the Second World War, digesting declassified files and interviewing surviving relatives. Thomas also produced the film and co-stars as Hall; Lydia Dean Pilcher directed.

Too often, Thomas says, war and espionage films relegate women to thankless romantic side plots. Shaping her script around real-life SOE agents Hall, Vera Atkins, and Noor Inayat Khan allowed her to dissect something far more interesting: “the psychology of what it’s really like, day in and day out, to be a spy on the ground.”

Though A Call to Spy takes place in Nazi-occupied France, Thomas found ways to shoot in the region throughout 2018. “It’s an incredible place to make a movie,” says Thomas. “I like to say my goal is to be the female M. Night [Shyamalan].”

While the film was also filmed in New York and Budapest, there’s a Philly undercurrent throughout — shots and setpieces flashing glimpses of the Art Alliance or Newlin Grist Mill, for instance. There’s also a sequence featuring Villanova’s Ardrossan, the enormous Georgian Revival mansion built in 1911 for the Montgomerys, the Main Line bluebloods who inspired The Philadelphia Story. As it’s named after the clan’s ancestral Scottish home, Ardrossan’s architecture “is an exact replica of the types of estates in Scotland where these spies historically trained,” explains Thomas.

The physical and mental gauntlet the protagonists endure there approximates the tactics of the SOE, known colloquially as Great Britain’s “Ministry of Ungentlemanly Warfare.” The Winston Churchill-approved initiative stood out for its then-unconventional recruitment of civilians, foreign nationals, and women to execute Allied tradecraft. This is how Hall, a charismatic, highly educated, multilingual Baltimorean with diplomatic aspirations, joined the cause.

Blackballed from foreign postings due to her gender and physical limitations — in her 20s, she lost part of her left leg in a hunting accident, and wore a draconian prosthesis — Hall was recruited to develop a clandestine intelligence network, codename “Heckler,” in Nazi-controlled Lyon in 1941.

Juggling assumed identities and ever-changing disguises while operating under constant threat of capture, Hall and her assets nonetheless earned their ruthless and efficient reputations. Hall intercepted sensitive Nazi signals and codes; supplied agents and rebels with money, weapons, and resources; and orchestrated numerous rescue missions, guerrilla attacks, sabotage operations and prison breaks.

Radhika Apte, a big star of Indian stage and screen who’s begun appearing in more English-language fare, portrays Noor Inayat Khan, the ace SOE radio operator whose desire to earn military valor for fellow Indian Brits conflicts with her pacifist convictions. Stana Katic, perhaps best-known from ABC’s Castle, is Vera Atkins, a Romanian-Jewish codebreaker and prolific recruiter responsible for bringing dozens of female agents into the SOE fold.

Thomas did tweak some chronology in A Call to Spy, uniting her trio in a single timeline for storytelling purposes. “They were each the firsts in their field,” she says. “Virginia was the first female field agent, Noor was the first female wireless operator, and Vera was the first and only spymistress who recruited women. The purpose was to explore this greater theme of people from different nationalities and religions resisting against a common evil — a more global story.”

Whether the setting is Boathouse Row, a Wall Street boardroom, or war-torn 1940s Europe, Thomas grounds her films in the extraordinary accomplishments, and human complexities, of everyday women. “What I really wanted to showcase was their grit and determination to do the job, and to show the power of the individual,” she says. “We can all stand up for whatever we believe in.”

A Call to Spy

Screening with Sarah Megan Thomas, Tuesday, Sept. 29, 7:15 p.m., $12. PFS Drive-In at the Navy Yard, Admiral Peary Way and League Island Boulevard. Advance tickets available at filmadelphia.org. A Call to Spy opens in select theaters and video on demand on Friday, Oct. 2.