Director: Miguel Gomes
Cast: Laura Soveral, Ana Moreira, Teresa Madruga, Henrique Espirito Santo, Carloto Cotta, Ivo Müller, Isabel Muñoz Cardoso 
Certificate: 15

Hands up if you can tell me word for word a conversation you had with someone 30 years ago. No? Tabu is a film that’s smart enough to realise that. One half present-day pain, the other a startling flashback, it filters memory through silent cinema (the title nods to F.W. Murnau) – reliving the romantic past of Aurora (Soveral), a bitter gambling addict in her 70s, via the hazy, black-and-white medium of film.

We first meet her through her kind neighbour, Miss Pilar (Madruga). Called upon by Aurora’s loyal maid, Santa (Cardoso), Pilar is asked to help locate Aurora’s old friend, a man who once had a fling with the selfish, bonkers old biddy.

Sound simple? Be warned: those three lines of text are expanded to 45 minutes. It’s a slow burning first half – too slow, in fact. We watch as Pilar drives through Lisbon and Aurora slips into dementia while making racist comments about the help. It’s intriguing, sure, but it takes effort to stay interested – too much effort, in fact. It’s telling that three people in my screening walked out of the film within the first 30 minutes.

But if you can stick with Tabu, the pay-off is excellent; a moving, surprising look back at a tragic love affair. Young Aurora (Moreira), it turns out, used to live in Africa, near the titular mountain, with her husband (Müller). Life is good. She’s happy. Or, at least, she thinks she is until Ventura (Cotta) comes along. He’s hot. He has a moustache. And he’s in a sub-Beach Boys pop band. (He plays the drums.)

The band is just one of several flourishes that Miguel Gomes rolls out: every now and then he pauses the action, sitting there and letting the group play a few musical numbers for no real reason – just because they sound good. His visuals are equally bold, switching from 35mm in present-day Portugal to grainy 16mm footage for the past; a subtle, but evocative change in stock that makes a stack of difference.

Sumptuously shot by Rui Poças, Tabu brings out the vibrancy of the African landscape with only monochrome paintbrushes to play with. And then it removes all the dialogue, leaving Old Ventura (Santo) to narrate the final 60 minutes in voiceover. Does it feel like an audiobook on a screen? Yes. Is that a problem? No. Tabu breaks the rule of showing and not telling and that willingness to breach conventions marks it out as an intelligent creation. Even the prologue is a witty refraction of memory through cinema, putting us in Pilar’s seat as she watches an Out of Africa-style intro to Ventura (and a moody crocodile) in a darkened theatre.

If only the rest of the first half were as engrossing. Soveral and Moreira are both brilliant as the lonely Aurora, but if you’re not engaged when the interval comes around, the carefully observed detachment of the denouement - complete with lengthy letter-writing sequences - will only alienate you further. As 5 Live’s podcast would say, there’s a lot of Shawshank before the Redemption.

Tabu is out in UK cinemas now - and may not be for much longer. So if you want to see it, move quickly.

Tabu UK trailer