Bullock and 2 young children set off down a river to sanctuary, blindfolded, because you'll commit suicide if you see the dark malevolent force that has infected the planet.

Swapping between the river trip and how it all started 5 years ago, this is a really tense and sometimes almost unbearably hard to watch chiller. The force is never explained or seen - definitely for the better - but remains a frightening presence throughout. The cast are terrific, but Bullock is something else, delivering a stonking performance which not since Sigourney Weaver as Ripley has so well combined vulnerability and toughness. This is particularly moving in her relationship with the children where she pulls no punches in her treatment of them to keep them both alive.

There are definitely a few plot holes which needed tidying up, but this is definitely one to catch. It never lets go, keeps you longing for a happy ending (I won't say) and finally leaves you exhausted.