The rise of the far right throughout Europe and the escalation of racial violence – including in the UK since the Brexit referendum – lends discomforting context to this intermittently powerful drama by the German director Fatih Akin.

In the Fade charts a woman’s ferocious desire for justice after her husband and son are killed at the hands of neo-Nazis. The film is at its most powerful when considering its heroine’s grief, vividly brought to life in a superb performance by Diane Kruger. But it comes horribly unstuck with Akin’s misguided decision to turn terrorism into the stuff of revenge drama. It’s an odd affair, which grips and fumbles in equal measure.

A brief, upbeat prologue introduces German Katja (Kruger) and her Kurdish husband Nuri (Numan Acar), a Hamburg couple who are a little rebellious and madly in love. We first see them marry while he’s in prison, convicted of drug dealing. Fast-forward a few years and he appears to be redeeming himself by giving financial advise to the Kurdish community. They have a funny, sweet six-year-old son, Rocco, and are a strong family unit. Then one day a carefully planted nail bomb shatters the idyll.

The opening section is very well handled, Akin using a low-key, realist approach to chart the horror and shock of the attack, then Katja’s descent into grief. Both her and her husband’s families are at hand, mostly making matters worse; the police seem focussed on Nuri’s drug-dealing past, implying that criminal ties led to his death; Katja uses drugs to numb herself.

Kruger plays these scenes with an admirable intensity and an intelligent awareness that grief does not need to be touchy-feely. Katja rails and despairs, fluctuates between focused attention and introversion, anger and despair. She has very sharp edges, and the cinematography seems to place a rain-lashed bubble around her pain, lest it ignite.

The police have been more conscientious than they appeared. And when the bombers are apprehended, they turn out to be a chillingly unrepentant pair of neo-Nazis.

At this point, In The Fade could have segued from the domestic to the courtroom with little need for embellishment; after all, there’s more than enough meat in the tension between personal tragedy and the studiously careful confines of the law, where even hate crime has to be treated dispassionately. Unfortunately, Akin has other plans, for which the trial is just a stepping stone. And it’s from this point that the film starts to unravel.

The director and his co-writer Mark Bohm were inspired ¬by the real-life racist murders between 2000 and 2007, primarily of Turks and Kurds, said to have been carried out by the neo-Nazi group National Socialist Underground. That trial is ongoing. Akin’s own court scenes are both compelling (there’s a grim fascination in seeing evil attempt to get itself off the hook) and ridiculous. I have no idea if the German legal system is really like this, or whether Akin has imagined a setting that requires witnesses to give evidence literally over their shoulders (courtside masseurs would make a mint here) and where judges allow blatant manipulations and lies without objection. The defence counsel couldn’t be more evidently venal if he tried (albeit well played by Johannes Krisch).

While these scenes challenge credibility, the director needs the contrivances in order to fulfil his preposterous endgame – the cheated Katja as tattooed avenger. What happens in the film’s final third is lamentable drama, a disservice to the character that Kruger has created and an unintentional affront to anyone who’s actually been victim to any kind of terrorism.