This year political satirist, comedian and presenter Jon Stewart leaves behind his long-running Daily Show after a decade at the helm. And you can’t help but feel that part of his reason for leaving is to pursue other creative avenues, the first of which is becoming a fully-fledged filmmaker in his own right.

His debut feature is Rosewater and with it he shows great promise as a filmmaking talent to watch for the future. It tells the deeply political true life story of Iranian-Canadian journalist Maziar Bahari (played by Gael Garcia Bernal) living in London with his pregnant wife. While out in Iran covering the infamous 2009 presidential election and as a result of a spoof interview he did that year with Jason Jones of The Daily Show, he is detained by Iranian forces and brutally interrogated for months under suspicion that he is actually a spy.

The first third of Stewart’s film is basically a “class is in session” lecture (in the best sense of the word) about some very recent, still-pertinent world history that tries to educate anyone not in the know about the Iranian political situation and people living in it. It’s never laborious, however, choosing to put things in context rather than attempting the impossible task of exploring the infinite complexities of East vs. West ideology, politics and religion. There’s heavy use of some rather nifty visual trickery in this first segment of the film such as projections of news footage and graphs appearing on walls as Bahari walks down the street and this gives the film a unique, stylish quality to lift it above being a depressing misery-fest.

That lightness of touch is further achieved in the film’s surprisingly carefree sense of humour that, while it never undermines or undervalues the seriousness of its subject matter in any way, sees the funny side of the warped logic used to justify Bahari’s imprisonment and constant spotlight of suspicion and deep-rooted mistrust shone upon him.

That being said the film takes its complex and difficult themes very seriously, none more so than in the harrowing interrogation scenes that make up most of the film’s runtime. They’re by no means visually graphic as some movies of this kind have been in the past (it was said they didn’t want to numb the audience to the torture by being relentlessly brutal about it) but Stewart rather skilfully conveys the sense of constriction, helplessness and desperation felt by Bahari as he is left to rot in a tiny solitary room – with only conversations with his imagined dead father as company – in between intensely traumatic bouts of so-called questioning at the hands of a particularly ruthless interrogator. Sometimes it might feel like those scenes get a tad repetitive but that only further highlights the relentless nature of his imprisonment.

Much of the film rests on the shoulders of Bernal and he carries it with great aplomb. It might be a little bit odd that Stewart would cast a Mexican actor as an Iranian but Bernal is such a terrific performer able to embody many things – as he has proven in everything from Alejandro González Iñárritu’s Amores Perros to Michel Gondry’s The Science of Sleep – and he conveys all the emotion of a driven and passionate man with his feet swept from under him and his freedom wrongly taken away. Equally good is Kim Bodnia (of Scandinavian TV drama The Bridge fame) as the interrogator who gives the film its name because of the sickly sweet scented perfume he wears. Bodnia, in tandem with Stewart’s script, never paints him as a two-dimensional monster motivated by pure evil but as a fully-formed, believable human being capable of terrible things for all the wrong – or at least misinformed – reasons.

Many first-time directors will choose a low-fi character drama as their first outing, something that allows them to gently cut their teeth in preparation for their big project to come. Not so with Stewart who fires right out of the gate with both barrels blazing, delivering an altogether compelling, shocking, complex and important portrait of a recent injustice that deserves to be told and shouldn’t be forgotten.