How does it feel when your teenage daughter goes missing? Runners poses the question that even a heartless tabloid hack might hesitate over, but looks forward two years after Rachel's disappearance, when sympathy has waned. Her father (a role well suited to Fox's seedily neurotic screen manner), alone in his conviction that she is alive, and encouraged by a self-help group where he meets Asher, a woman who has similarly lost her son, goes to London to find her. The amazing thing is that he does - briefly - and what seems to be just a behind-the-headlines story of an obsessive odyssey becomes an impressively ambiguous thriller. The unfancy realism of Sturridge's direction emphasises that this is a small film; but unlike, say, a TV drama-doc, it doesn't just flesh out a contemporary social problem. Rather, schadenfreude gives way to shaggy dog as writer Stephen Poliakoff weaves a quirky tale out of the loose ends of the here and now.