THE STORY: In an alternate universe, dinosaurs did not become extinct and have learnt to create communities. Arlo comes from a family of farming dinosaurs. He tries to be a good son to his father, but is held back by his fear of everything. A raging river sweeps him far from home one day.

He makes the return trek, dogged by a feral human boy he names Spot.

Just as you are about to relax into what looks like a movie for the under-10s, something happens to turn it all upside down.

Arlo, the lost young dinosaur, sees someone close to him die in a horrifying way early in the movie.

In one of the best horror-movie character switch-ups to happen in recent times, someone who at first appears to be a friend does something to prove that first impressions can be fatally wrong.

The opposite happens later, when big scary creatures turn out to be the best companions a young herbivore such as Arlo (voiced by Raymond Ochoa) could have.

Then there are gags - including ones about psychedelics - that will sail over the heads of children.

Reports about troubled productions most often lead to disastrously poor films, but in this case, a turbulent six-year gestation appears to have done The Good Dinosaur no harm, while shoring up the idea that at Pixar, failure is always an option if a story needs work.

First-time director Peter Sohn, a replacement for original helmer Bob Peterson, is ready to make scenes as strange and scary as a child's survival story need to be.

In this, it bears kinship with Up (2009) and it should come as no surprise that Peterson wrote and co-directed the story of a boy and an old man exploring a lost jungle.

As in Up, there are moments here - two, to be exact - where your tear ducts will spring a leak.

Why does Pixar do this? At this point, the only valid theory is that it is a secret sadist.

But the comparisons with Up end there. The Good Dinosaur is a masterpiece of minimalism next to the 2009 movie.

There are almost no references to our world unless it is to up-end expectations, to teach that appearances can deceive.

Because there is so little by way of explanation, when Arlo meets someone new, he is as much in the dark as the moviegoer is. There is a shared anxiety that never lets up.

Up's Gauguin-inspired jungles are stunning, but in this movie, the impact comes from how uncannily three-dimensional the landscape looks, especially its water effects.

The rocks, trees, rivers and mountains are so real and breathtaking, it makes you itch for a pause button to linger and to stare.