Kate Winslet, Idris Elba and a dog up a mountain. Who thought this was a good idea?

It comes as an enormous relief when the mountain lion turns up.

Idris Elba, Kate Winslet and a dog find themselves stranded on a snowy peak somewhere between the western states and New York City. They don't have to worry about water, but, once they've got through the candy bars, food is going to prove a problem. Within minutes, many viewers will find themselves wondering if the producers will allow the characters to address the Labrador in the room. Yum, yum! Then again, Kate Winslet and the dog might eat Idris Elba. They could last for months up there.

Anyway, before we come to that unlikely crux, Kate shoots a mountain lion with a flare gun and we’re left to ponder less uncomfortable quandaries. How will they get off the mountain? Will they survive their ordeal without a terrible love scene? Who thought this was a good idea?

Based on a novel by Charles Martin, the film imagines that Elba, a surgeon, and Winslet, a photographer, are delayed at a mid-western airport and elect to share the cost of a private plane. Following pilot Beau Bridges's unintentionally comic stroke, the panicked camera buzzes in and out the aircraft as it hurtles to an unlikely soft landing on a mountainside. Eventually, man, woman and dog come to. The radio is broken. Phones don't work. The route to safety is unclear.

Relying on some absurdly clunky plotting to reveal desperate secrets – Elba carries around a dictaphone containing life-changing conversations – the film cracks merrily along Guilty Pleasure Ravine for its first hour or so. If you want an implausibly lavish high-concept episode of an afternoon soap opera then look no further.

Sadly, The Mountain Between Us cracks apart when – feet nearly hacked off, skin blued by exposure to icy water – the two fall into a romantic relationship. They swoon in ways no half-dead people do. They say things nobody ever says. It's good to see a rare movie romance that casts a black actor opposite a white one. What a shame that, for unrelated reasons, the script allows no possibility of this particular romance gaining emotional traction.

Still, at least the dog remains uneaten.