Director Julia von Heinz takes on a lot here, wrangling a lightly comedic father-daughter road-trip buddy-movie out of her adaptation of a 542-page book, unpacking generational trauma, the legacy of Auschwitz and institutionalised antisemitism. It’s a curious mix, alright. Based on Lily Brett’s 1999 autobiographical novel Too Many Men, von Heinz finds her own yo-yoing tone, as idealistic, frustrated New York journalist Ruth Rothwax (Lena Dunham) locks horns with her garrulous, over-sexed father Edek (Stephen Fry), a Holocaust survivor. To be fair, von Heinz actually streamlines the source material, losing a strand in Brett’s book in which the ghost of Auschwitz commandant Rudolf Höss joins the pair on their trip — keeping it would quite possibly have been too much for one little movie.

A year after her mother died, keen to explore her own roots, Ruth arranges a trip to Poland to see where Edek grew up before the Nazis invaded, forcing him and his family into the ghetto, and then the camps. She wants to visit Edek’s childhood town, Łódź, despite his apparent indifference: he resists, but she persists, as they go back to his family home, and then, inevitably, to Auschwitz-Birkenau. “It’s not a museum, it’s a death camp,” she righteously insists to well-meaning stewards. She seems consumed by the past he’s run away from, she wanting to connect with it, he wanting to leave it well behind. He has moved on – or so he likes to think.

Von Heinz grapples with the generational divide on macro and micro levels, as the pair both come to terms with what Edek – and Polish Jews – went through while also, yes, learning about each other. As a drama, it isn’t quite convincing enough. Some attempts at fleshing out Ruth’s character – she has something of an eating disorder, and is prone to self-harm – feel, here at least, a little superficial, perhaps even a little cheap. Fry’s heavy Polish accent, with its comical broken English (straight out of the novel), feels a bit shticky, at worst reminiscent of Borat. Yet underneath it all, and in their eyes, you can feel the investment from Dunham and Fry, who both hail from Jewish mothers. You can see how much this material means to them (Dunham is a producer) and such unmistakable personal intensity does a lot of the heavy lifting, carrying the film into more emotional territory here and there.

This is not particularly ambitious cinema; perhaps it might have been, with Rudolf Höss’ ghost along for the ride. We will never know. As it is, despite everything it packs in, it’s well-trodden territory; the comedy is, to be polite, gentle, and it’s all painted in broader strokes than the material deserves. Its sincerity, though, makes it worthwhile. You can feel the intention, at least. This is about a hijacked past and the compartmentalisation of it, mentally and physically, and most effective is the vivid recreation of post-Iron Curtain Poland — a grim, ghostly relic that can’t wholly disguise the historical horrors. Filmed in dilapidated, unloved, unkempt corners of Germany, the recreation of 1991 Warsaw is depressingly drab, the sky eternally grey, the interiors brown and beige, like colour — and joy — has been drained from the place. As if the whole town is ashamed of itself.