Kevin Macdonald’s clumsy marriage of a YA romance and a harrowing WW III survival saga is far from original. But the ever-surprising Saoirse Ronan (Atonement, Hanna) provides the glue that makes it all work. A snotty American teenager is unloaded for the summer with her English cousins (including the dishy George MacKay). She eventually lowers her barriers and comes to see this fragile, unsupervised group of kids and teens as the family she never had. Then someone nukes London and the film morphs into a fashionably begrimed thriller, in which the story effectively adheres to her POV.  Well worth seeing. Japanese title: Watashi wa Ikiteikeru. (101 mins)