In June 2009, Maziar Bahari, a London-based, Canadian-Iranian journalist and documentarian, was among hundreds of people arrested in the wake of the contested Iranian presidential election. Bahari was held and forcibly interrogated for 118 days in Tehran’s Evin Prison.

Shortly before he was arrested, Bahari had filmed a tongue-in-cheek interview with The Daily Show's Jason Jones. That interview became a sticking point for his interrogator, who decided that Jones was an American spy.

Bahari's ordeal was chronicled in the 2011 memoir, Then They Came for Me: A Family's Story of Love, Captivity, and Survival. It was subsequently adapted for the screen and directed by The Daily Show's Jon Stewart. The result is Rosewater, an expensive ($5 million-$10 million), if heartfelt, apology.

So far, so worthy. Hell, the film even stars that celebrity good-guy and bleeding heart, Gael García Bernal, as Maziar. But by focusing almost entirely on the relationship between Maziar and his interrogator, Stewart soon mines dry humour from Stockholm Syndrome and increasingly wild allegations. Brutality is played down, humanity is trumpeted.

Elsewhere, the first-time film-maker finds interesting things to do with Bahari’s family history: memories are projected onto shop fronts as the protagonist strolls down the street, and family members are conjured as companions as he struggles with four months of isolation.

We break from Bernal and Bodnia’s excellent two-step to a wider world where hashtags float across the screen and news reports provide context. Never mind the haters: Stewart is out to celebrate the democratic potential of the internet age.

There's an interesting contrast here between this tightly focused, intimate picture and Bahari's own films (including To Light a Candle, a documentary about the persecution of Bahá'ís in Iran), which are characterised by a broader view. But there's plenty to be gleaned from Maziar's small prison cell.