THIS is one of those rare American thrillers that does keep you guessing right until the very end.

It is shot all the way through its 120 minutes from the point of view of Smartphones and computer screens.

That may sound like a gimmick but it is essential to the type of story-telling adopted by the first class writers and director.

You cannot take your eyes off the screen ... and the screens before you.

At first, I thought this would be irritating but as we are all worryingly dependent on such devices we can relate to it.

The diverse methods we all use to communicate – rightly and wrongly – with each other are brought to our attention.

This is a unique approach and worth seeing even for the reason of highlighting just how much society is reliant on social media.

It is, at times, scary that we depend on mobile so much probably without realising it.

As a way to tell a tale it may not sound like an enjoyable cinematic proposition.

But it is.

When I left the cinema I didn't want to go anywhere near Facebook or Instagram for a while.

Ultimately, that is a good thing.

Maybe there is a moral here ... Use social media don't let it use us to the point where it is something we cannot seemingly live without.

One lesson that merges is that we sometimes don't really know each other as much as we thought we did.

So what makes this modern day, state-of-the art movie so compelling as entertainment?

It centres on a caring father David Kim, played by Asian-American John Cho with astonishing intensity.

I won't give away too much here of the early tense plot, but suffice to say, David communicates with his 16-year-old, piano-studying daughter Margot (Michelle La) via social media but then she suddenly stops returning his calls.

Messages mount up and he is perplexed by her silence.

Worried sick and at his wits end, he reluctantly contacts the police.

With the help of an award-winning, no-nonsense police officer, Debra Messing, they embark on a joint roller-coaster piece of on-line detective work that includes televisions, CCTV and other security camera work.

It is a slick, consistently clever, gripping whodunit with red herrings, twists and turns on every corner.

It bravely breaks the mould of thriller crime stories.

Click on to a cracker - four stars

On general release