“Christine did not live, or love, as most people do,” writes Clare Mulley, the author of The Spy Who Loved: The Secrets and Lives of Christine Granville. As Mulley argues, “she lived boundlessly (...) prepared to give her life at any moment for a worthy cause.” Christine Granville was, in fact, Krystyna Skarbek, a Polish agent working for the UK’s Special Operations Executive, who acted as a British “joe” (to use John le Carré’s term) during the Second World War. She’s also the titular heroine in James Marquand’s latest feature The Partisan, which is an honest but fairly messy account of the dangerous and complex life Skarbek once led. This Polish-British co-production is released via Miracle Communications tomorrow, 3 October, in the UK.

It’s clear that The Partisan’s director takes Mulley’s quote to heart. By depicting the most crucial junctures in Skarbek’s professional career, Marquand chronicles a story of a woman haunted by personal demons and doubts. Yet, as we learn from the very first sequence of her interrogation, Skarbek has never been broken by anything or anyone. Paradoxically, it was actually Krystyna’s own psyche that became her worst enemy.

At times, Marquand is unable to maintain this balance between the personal and the professional. Characters from Krystyna’s past emerge as quickly as they vanish from the big screen, and the operations Skarbek participates in seem rather unclear to ordinary viewers who aren’t experts on this particular historical period. In this sense, it’s sometimes difficult to remain either immersed or invested in any of the film’s storylines.

It’s Morgane Polański - mostly known as a model and the daughter of Roman Polański and Emmanuelle Seigner - who leads the cast as Skarbek. The 32-year-old actress embodies the spy’s vitality and readily manoeuvres between the two sides of her ambivalent nature. For the most part, she acts just like a spy should – there’s some tangible indifference and apathy in her on-screen personality. But, at times of crisis, Polański is also able to show us Skarbek’s human side. What she likely lacks, however, is better direction from Marquand himself. There are a few scenes in which Polański’s histrionic reactions actually feel caricatural, even if the desired effect was to evoke contrary emotions.

Despite not being an ensemble film per se, given its heavy reliance on close-ups of Polański (whose traits are often reminiscent of her mother’s), The Partisan is full of unique cameos. Malcolm McDowell stars as Skarbek’s supervisor, and several well-known Polish thespians also make their appearance. Piotr Trojan is Krystyna’s lover, Agata Kulesza plays her steadfast mother, while Piotr Adamczyk steps into the shoes of a mischievous Nazi general who’s the film’s main antagonist and most memorable character.

Despite its flaws, from obscure exposition to the lack of a coherent narrative, Marquand offers up a relatively persuasive lecture, allowing us to revisit a chapter left untold by our history teachers back in school. The Partisan weaves its story around a significant figure who has been somewhat forgotten by modern discourse. And Marquand makes his audience care about Skarbek, even if we do find ourselves googling her surname after the final credits and poring over her Wikipedia profile. This sudden spark of interest might be the film’s greatest achievement, making us wonder what else Skarbek went through during her remarkable duty as a spy.

The film was produced by Poland’s Sisyphus Sp and UK’s Media Finance Capital.