Sometimes a film’s best moments come not in any particular shot, but in the gaps between them. We Need to Talk About Kevin, Lynne Ramsay’s brilliant and bracingly assured adaptation of Lionel Shriver’s novel about a mother whose teenage son commits an unspeakable crime, is just such a movie. It shows you one thing then shows you another, and asks you to connect the dots to dizzying, ferocious effect. Ramsay’s film – her first since 2002’s Morvern Callar – breezily dispenses with the structure of the original book, which read as a series of letters from Kevin’s mother Eva to her husband Franklin, in which she reflects on their sociopathic son’s misdeeds. Instead, we see Eva (Tilda Swinton), Franklin (John C Reilly) and Kevin (Jasper Newell as a child and Ezra Miller as a teenager) across four distinct time periods. There are snatches of Eva’s pre-motherhood life as a travel writer. There’s Kevin’s upbringing, in which a strange psychological feud is waged between mother and son from birth (at one stage, in an unsuccessful attempt to drown out her baby’s constant screaming, and possibly punish him for it, Eva parks his pram next to a pneumatic drill). There’s a fragmented account of the day on which Kevin commits his crowning, headline-grabbing atrocity. Finally, there’s Eva’s subsequent existence as one of the most hated mothers in America. Ramsay’s narrative cuts between these four strands freely and often, but she gives it structure with ingenious visual rhymes that force the audience to make links between Kevin’s crime and what came before it. Some of these are roaringly unsubtle – oozing jam sandwiches and splattery arcs of crimson paint make us think of, yep, blood – but the significance of others take a bit more decoding: one scene shows Eva spitting out fragments of eggshell she finds in a hastily-prepared omelette, and we can’t help but think of the way Kevin bit off his fingernails earlier, ejecting the clippings from his mouth and placing them in a neat row on a table. These visual parallels pose some tough questions, to which Ramsay has a lot of fun not giving us any straight answers. Do Kevin’s actions spring from nowhere, or are they somehow prefigured? Was he born evil, or did his mother make him that way? The chemistry Ramsay builds between Eva and Kevin is rich, ambiguous and scorchingly intense, and she’s helped along no end by a trio of terrific performances from her leads. Tilda Swinton is complex, brittle and totally plausible as Eva. Jasper Newell, the young actor who plays Kevin between six and eight years old, is the best kind of unsettling, with a nightmarish half-grimace smeared across his face like so much cheesy powder from a bag of Wotsits. Ezra Miller, as the teenage Kevin, is both entrancing and repulsive; two poles of a magnet in one person. He has a way with words that isn’t so much withering as herbicidal. Miller’s Kevin has nothing in common with your common-or-garden paedophobic horror villains such as Damien from The Omen, but Ramsay has a hoot playing up to the stereotype in a brief Halloween scene in which Eva is tormented by young trick-or-treaters. The sequence is set to Buddy Holly’s Everyday, but, while a lot of the soundtrack choices including this one are fairly on the nose, others are completely inscrutable: a few scenes even end with a twangy oriental flourish, like the announcement of a tableau in a kabuki play. This is Ramsay’s most accessible film by some distance, and even its ethereal opening scenes – a voile curtain billowing in front of an open patio door, and a seething crowd at a Spanish tomato festival, slathered in red pulp – turn out to be grounded in grim reality. It’s testament to her skill as a director that even though her adaptation of Shriver’s book is a ruthless one, the film feels entirely faithful to its spirit. More importantly, Kevin is a piece of vital, visceral cinema in its own right; teeming with words and images to mull over, pick apart and talk about. And you will need to talk about it.