It looks like Daisy has been sent to England as punishment, because while the cousins are playful and independent and comfortable with things like dirt and waterfalls, Daisy wears a pound of makeup, dresses like she’s never been outdoors in her life, and carries a load of resentment. Other things are off from the start.

There’s a low, rumbling cacophony of angry voices; when she gets to Heathrow airport, instead of going to a parking lot, Daisy’s 14-year-old cousin walks her under a fence and through some woods to a Land Rover which he drives the many hours to the farm.

There are also virtually no functional adults in the entire movie – the British aunt leaves for somewhere with only a brief and careless goodbye, so Daisy is alone with four cousins, three boys and one little girl. Besides that, a newspaper headline says something about a bombing in Paris.

The world is unsettled. Right after Daisy gets over her pouty attitude, and starts to like the waterfall, the swimming hole and the older cousin Eddie – there’s a sudden wind and something like snow.

Terrorists have exploded a nuclear bomb in London, and even in this rural area the social structure comes unglued.

"How I Live Now" is scary because director Kevin MacDonald keeps the terror restrained. Gangs don’t roam the countryside; no zombies eat their way through the population; the country doesn’t go up in flames.

Little things signal the disruption and what may be civil war. Power goes off; smoke wafts in the distance; a government official comes by with the word that everyone has to evacuate. But these independent kids won’t go; they’ve been playing in a paradise of gorgeous fields.

They hide in their barn, until one night bullets ricochet off the stone walls. It’s the army and the five young people are corralled, the boys separated from the girls.

Eddie whispers to Daisy that they should find their way back to the farm – and off they’re taken. It’s implied more than shown, but England is in civil war.

When the big-budget action filmmakers do apocalypse, they like to show the enemy vaporizing grand symbols -- the White House, the Washington Monument. It’s showy, but Kevin MacDonald doesn’t go for the dazzle -- he gets under your skin. 

MacDonald is the grandson of near-legendary Emeric Pressburger, co-maker of "Black Narcissus", The Red Shoes and I Know Where I’m Going, and he knows from subtle.

The movie doesn’t name the terrorists; like the kids, the audience is left in limbo. You only see the other guys once, off in the distance.

Episodes of social breakdown only come a couple of times. It’s mostly hinted at, and again the movie’s restraint makes those things count. You don’t get over them.

You hold onto the sight of Daisy vomiting at the sight of bodies at a deserted farm; just one brief sighting of unruly young men, puts the worry of rape into the film for the duration. When Daisy and her little cousin tromp through a forest, you feel on edge with her. Every time a leaf rustles, you wonder if she’s about to be attacked.

You could call "How I Live Now" a coming of age story, but that’s not quite it. Daisy gains competence in tiny increments. She grows alert. She takes charge and the sullen teenager passivity vanishes.

The color in the film returns to something like the actual world; it grows less harsh, less twisted.

British films made during World War II stressed the idea that staying British – going to work, delivering the mail, going to concerts and dances – normalcy, would ultimately defeat the German attacks. 

"How I Live Now" has the same determination. The heroism is in Daisy’s persistence.

Set in the near-future UK, Saoirse Ronan plays Daisy, an American teenager sent to stay with relatives in the English countryside. Initially withdrawn