Opening this year’s Kinoteka Polish Film Festival (details at The Iron Bridge is a story that is small in construction but deals with some of the most powerful and profound of human emotions.

Told partly in flashback we first see Kacper (Bartlomiej Topa) visiting Magda (Julia Kijowska) his lover and the wife of his friend/colleague Oskar (Lukasz Simlat) who has been trapped in a mine shaft following an accident. Taken straight to the colliery Magda is briefed on the technical details of the incident and assured that the company will try everything to rescue him.

Interspersed with the accident there are flashbacks of varying length to the relationship between the three. It’s a common enough scenario. Invited over for a meal, too much drink, pass out and lust over powers the lovers. From that blossoms a full-blown affair that Oskar seems to be vaguely aware of. He visits Kacper to talk about Magda, with a bottle of vodka, when she turns up (not having opened Kacper’s text). Trying to read Oskar we can’t quite tell if he’s that surprised. What’s palpable is the awkwardness of the other two whom we see reflected in the hallway mirror scrabbling for words.

However his suspicions are raised when Kacper allocates one of the remotest seams for him. The looks and comments from Oskar tell all. The background now laid, the final third of the film concentrates on the rescue and the lovers’ handling of the situation.

Written and directed by Monika Jordan-Mlodzianowska it’s a classic love triangle, though it’s the intricacy and nuances of the main characters make this engrossing. It’s about the details of peoples’ expressions and inflections as when Oskar is forced onto the shift while Kacper makes his excuses not to go down; there are few words it’s all on his face. When after their initial tryst, Kacper – clearly feeling guilty - ignores Magda though she gives him a goodbye peck on the cheek as she and Oskar leave, because she forgot to greet him.

As the films shifts away from the exposition to the rescue Kacper’s guilt starts to take over; the idea of the borehole is desperate he has if they can do it, it’s merely to give Magda hope. And when the borehole is started his neediness to be involved in all aspects of the operation is given short shrift with a cutting remark from operation head Mikolaj (Andrzej Konopka) suggesting that he knows the score. The last third is an intense two hander between Kacper and Mikolaj they try to locate Oskar.

There isn’t any doubt that Kacper and Magda feel deep regret about their actions but it is Kacper who sent Oskar down the shaft that is plagued with remorse looking for every possible angle to save him. It’s not about Magda as that relationship is finished, as it is with Oskar, regardless of the outcome. As such its convincingly altruistic.