Watch: Trailer For Kevin Macdonald’s Apocalyptic ‘How I Live Now’ Starring Saoirse Ronan

In an end-of-the-world-heavy summer, we’ve seen blockbusters in which the world was saved (“Man Of Steel,” “World War Z”), cancelled (“Pacific Rim”), ended (“This Is The End”), and whatever happens in Edgar Wright’s imminent “The World’s End.” So far, it’s been a fairly lighthearted take on the apocalypse. But as the days get shorter, the films look to get bleaker, as a trailer for a new young-skewing end-times picture demonstrates.

Based on the best-selling prize-winning novel by Meg Rosoff, “How I Live Now” is the latest film from director Kevin Macdonald (“Touching The Void,” “The Last King Of Scotland,”), and toplines Saoirse Ronan as an American teen, Daisy, who comes to stay with distant relatives in a time of strife. She ends up falling for one, Edmond (rising star George MacKay, of “The Boys Are Back”), but their affair is cut short when a nuclear device goes off and England is occupied, forcing Daisy and Edmond to desperately fight for survival.

It’s dark stuff, if the book is anything to go by.