"Cecilia" (Keira Knightley) has fallen for "Robbie" (James McCoy) - a man well down the social ladder from her family and their stately home. It's love, though, and the young man is doing his best to fit into their privileged world by studying (at their expense) at Cambridge with a view to becoming a doctor. Meantime, following a scene that she has completely misinterpreted and the reading of a letter that wasn't any of her business, their behaviour is being rather unhealthily scrutinised by her thirteen year old sister "Briony" (Saoirse Ronan) who soon becomes fixated on the couple, on destroying the couple and to that latter end she concocts a story that not only achieves her goal, but sees "Robbie" wrongly incarcerated for a fairly heinous crime. The war intervenes and that gives the lovers a chance to recalibrate their feelings for each other whilst the now more mature "Briony" (now Romola Garai) with whom her sister has become estranged, is having a serious crisis of conscience and travels to London to be both a nurse and to take responsibility for her behaviour five years earlier. This is a complex and detailed piece of cinema and McAvoy delivers really well as the honest and decent lad caught up in a web of deceit and envy. Knightley is less effective - but still contributes well enough as the truth is finally known before an inevitable tragedy strikes. It's a story about the ramifications of a lie, but it's also about people's abilities to love, forgive and to judge. Loyalty might only be skin deep but regret lasts for ever, and ever might not be so long as you might hope. Dario Marianelli has created a masterful score to accompany this story and the writing and Joe Wright's subtle direction ensure we steer well clear of the melodramatic and the sentimental as the denouement looms and Vanessa Redgrave appears for a quite fitting final mea culpa. A straightforward British period drama this isn't and it's well worth a watch on big screen for the a cinematography that marries the rustic charm of rural England with the horrors of bombs, bullets and blood poignantly.