Still on a mission to cheer up the mother-in-law after last week’s failure with the aptly titled Blue Jasmine, this week’s outing was a bare notch up from the last. Director Kevin Macdonald is no slouch when it comes to movie-making, and I loved The Last King of Scotlandand Touching the Void, but it is a calculated risk to take a teen book and try to adapt it for universal appeal. With a 15 certificate and warnings of excessive violence and content of a sexual nature, mother-in-law was anxious before the film even started!

Set at some date in the not-so-distant future, American super-brat Daisy (Saoirse Ronan), all Goth and therapy, is dumped on her English cousins by her Dad who has a new family and no room for her.

Arriving at Heathrow, she is spirited away by 14 year-old Isaac (Tom Holland) in a clapped out Landrover to the middle of nowhere. She finds herself in a Bohemian fairyland, complete with unicorns, mad dogs and her eccentric relatives who are left in glorious unkempt isolation while their mother, Aunt Penn (a sophisticated Anna Chancellor) is engulfed in saving the world. For England is in a state of high alert due to a terrorist threat, which culminates in a nuclear bomb over London.

Railing against the less-than-hygienic state of her new home and her crazy cousins, Daisy is nevertheless drawn to the strong and silent oldest boy, Edmond (George MacKay), who soon begins to break down her barriers. When the apocalypse reaches their doors she is forced to take charge and to look after feisty little Piper and fulfill her promise to Ed to take her back home.

The film brings to mind another old childhood favourite, The Incredible Journey,which recounts the hardships faced by three pets as they show courage and loyalty to find their masters in an epic crossing of the Canadian wilderness. Daisy discovers her inner strength, even while repeating the mantras of her therapy in order to try and survive the challenges of walking for days through a post-nuclear landscape of rivers, forests and bogs, being chased by marauders and seeing for herself the horrors of war at first hand. No wonder this only got a 15: some of the scenes are stomach-churning and, despite the modern fashion for kids to be exposed to great violence, not for the faint-hearted.

I particularly liked the performances of the young: Ronan – so good in the rather mediocre The Lovely Bones; MacKay, Holland and the delightful Harley Bird, who is apparently the voice of Peppa Pig. As you would expect from Macdonald, the film is beautifully shot, and the tension and suspense well executed, the madness of the British nicely done. The Third World War scenario was appropriately chilling.

However there are one or two cheesy moments – perhaps a nod to the younger audience – such as the hawk cliché; and the yomping goes on a bit too long,  as soggy as the marsh at some points. I was puzzled also as to why they so gaily wade through streams when wet clothes and shoes would have been more than a little tiresome. And Ronan’s face looks a bit too pristine by the end of journey, while Piper’s disheveled state is much more realistic. As for the end…well enough said. I suppose the film’s title had to have some meaning, which had been unclear until that point. I don’t think that’s a spoiler. So while mother-in-law and I found it less depressing than Blue Jasmine, it lacks the brilliance of a Blanchett, and the eclectic characterisation of Woody Allen. Not Macdonald’s greatest, but entertaining enough.