When parents “Maddie” (Rosamund Pike) and husband “Frank” (Matthew Rhys) get a call from their teenage daughter to say she has been in a road accident, they immediately get into their car and head to the quite far distant and remote scene. The rest of the film sees the couple trying to think what is best to do as the paramedic mother tries to help with an immediate problem whilst the father takes a more long-term and sacrificial view in the event of a worst case scenario. Things only get more fraught when another couple encounter “Alice” first and her folks become increasingly concerned that…