Eva Khatchadourian (played brilliantly by Tilda Swinton) is a former travel writer who’s ambivalent about her first pregnancy, and doesn’t seem to be able to connect with her newborn son Kevin, an infant who cries constantly and squirms away whenever she tries to hold him. Eva also suffers from postpartum depression and lack of sleep, which doesn’t make it any easier to connect with her ornery child. Eva as a new mother has the look of a concentration camp survivor. She is utterly tormented by her son–and her inability to feel maternal love for him.

As Kevin grows older, it’s apparent there’s something not quite right about him. Even as a very young boy of three or four, he has an unnerving, soul-piercing stare and never smiles or laughs. Though obviously very intelligent, Kevin isn’t out of diapers until he is 6 or 7, and refuses to engage with others, especially with Eva. He becomes disruptive at home and at school, and is always in trouble. Besides seeming to do things deliberately to upset Eva, Kevin bullies other kids at school, and encourages one girl, who has a severe skin disorder, to pick at her scabs. He’s sneaky and devious and shows no remorse for his bad behaviors. He seems to have only two facial expressions: sullen, or self-satisfied sneer when he’s gotten away with something.

There’s one poignant scene when Kevin becomes very sick and this is the only time he shows any vulnerability and allows himself to be mothered like a normal child. Here, while Kevin’s defenses are down and his mask of impending psychopathy is temporarily disabled, we can catch a fleeting glimpse of little-boy innocence and neediness and some emotion that may even resemble love. This scene makes you begin to question whether Kevin was born evil, or if his psychopathy may have been caused by Eva’s failure to bond with him as an infant.

The rest of the time, there’s an disturbing lack of innocence in Kevin. There’s an unsettling scene when Kevin, about age 3, is sitting on the floor while Eva rolls a ball to him. Not only does he fail to roll the ball back, but he fixes her with his unnerving hateful stare, a look you wouldn’t believe such a young child could be capable of.

As Kevin grows into adolescence (adolescent Kevin is played with subtle and chilling power by Ezra Miller), his misdeeds become more serious, and start to endanger not only his fellow students and teachers, but other members of his own family. At one point he does something unspeakable to his younger sister, Celia (a child his mother wanted and who is temperamentally Kevin’s polar opposite–a sweet and empathetic child), and then smoothly lies about it without showing a shred of empathy or remorse. The strain of raising this difficult child eventually destroys Eva’s marriage to Kevin’s father, Franklin (played by John C. Reilly), who disagrees with his wife’s belief that Kevin is disturbed and naively continues to insist he is a normal, loving child but that Eva’s attitude toward him is cold and unmotherly. Eva herself is torn–she seems to try her best to do and say the right things to Kevin, but it’s clear nothing is getting through to him and the strain is destroying her.

Things come to a head when Kevin commits a shocking crime at age 15 followed by another that is even more heinous. The entire film is told in flashbacks, in the form of Eva’s letters to her husband Franklin (who has left Eva and whose whereabouts are a mystery until the end of the film) and conversations between Kevin and Eva while he is in prison.

Eva tries to come to term with what has happened, to deal with the aftermath and ostracization by everyone the family knew, and most of all, what part she may have played in her son’s crimes. One question that runs throughout the film: was Eva a bad mother who caused her child to become bad, or was Kevin just born bad?

In the final scenes between Eva and Kevin while he’s in prison, it’s possible to see how sophisticated and subtle Kevin’s manipulations of Eva have become. Theirs is a complicated relationship: while he obviously hates her, it also becomes evident he has more respect for her than for his father, who always showered him with unconditional love and for whom Kevin has nothing but dismissive, snarling contempt.

“We Need to Talk About Kevin” (based on the 2003 book by Lionel Shriver) is one of the most chilling and thought provoking movies about psychopathy I’ve ever seen, and like other great psychological thrillers, it asks more questions about human nature than it answers.