There are two different, though interrelated, sources of dread in Lynne Ramsay’s We Need to Talk About Kevin. In addition to giving us flashbacks of a horrible crime that’s never fully revealed until the movie’s final minutes, Ramsay presents the bone-deep apprehension of Eva (Tilda Swinton), who worries her son’s threatening behavior is her own fault. Because it is Eva’s son Kevin who is responsible for the shocking act of violence, the film quickly becomes an unrelenting black hole of terror. By eschewing a linear approach to this material, Ramsay uses the first 20 minutes of screen time to get inside Eva’s head. We have no idea what the images mean -- she’s haunted by a curtain billowing from the air blowing through an open window and by her younger daughter wearing an eye patch -- but we empathize with Eva’s disorientation and fright. After forcing us into this thoroughly discomforting state, Ramsay introduces us to a conventional plot involving a series of scenes that indicate Eva fears something is wrong with her first child. We see a pregnant Eva at a prenatal class where she’s the only woman uncomfortable with her pregnant belly, and then the baby Kevin screaming all-day long when it’s just him and his mother, but cooing playfully as soon as his father picks him up. All this leads to an epic battle of wills between the mentally and spiritually exhausted Eva and the cold, unforgiving toddler that ends with a trip to the emergency room for the child. During this section of the movie, and it’s easily the best chunk of it, we’re not sure how responsible Eva is for her young son’s behavior disorders, and neither is she. The film gets at fears of parenting -- “am I just not cut out for this?” -- in a way few movies dare to go anywhere near. While Ramsay deserves credit, she can thank Tilda Swinton for giving her film so much power. This is an actress unafraid to play conflicted, but still capable of making us feel sympathetic towards her. There’s a scene in which young Kevin gets sick -- it’s the one time in the movie he begs for his mother’s attention and acts happy to receive it -- and in that moment Eva’s fear and loathing drop away. It’s a brilliantly played moment, and just one of many by Swinton. Sadly, the second half of the movie, after Ezra Miller takes over the part of Kevin as a teenager, becomes a lazy psychological thriller. Not lazy in terms of directing, as Ramsay knows how to keep the foreboding doom pressing on us at all times, but the script grows almost numbingly repetitive. What we witness is scene after scene of more and more outrageous and destructive behavior from Kevin, with nobody but Eva recognizing there’s a problem. There’s such an unwavering sense of doom that when dad buys him an archery set, it’s almost darkly comic rather than scary. Not once does this affluent mother visit a counselor, or ask friends for advice, or even discuss Kevin with her husband -- the title becomes a sick joke, because if only someone would talk about Kevin, tragedy might be averted. The movie grows frustrating, not in a challenging way that forces viewers to consider how they would act in Eva’s situation, but because all of the amazing work being done by Tilda Swinton is being used for a situation that starts to feel more like a horror movie than a real problem. The film settles for shock value when it promises so much more. The last scene between Eva and Kevin actually does allow a smidgen of light into Eva’s bleak world. In a way, she’s rewarded for being the only one able to see what her son really is, although she can’t understand it. Maybe the boy, in his own perverted way, really does love her. That’s an interesting endnote, but it doesn’t quite make up for how readily the film falls into a parent/child version of Fatal Attraction for so much of its second half. For Swinton alone, We Need to Talk About Kevin is worth seeing. Her rigorous commitment to making Eva a multifaceted human being helps fill many of the holes in the movie, even if it ends up feeling so much less ambitious than it could have been.