The pairing of "Eva" (Tilda Swinton) and "Frank" (John C. Reilly) is unusual, leading them to marry and start a family. Their son, the film’s central figure, proves difficult for her to connect with; his distress—crying spells or soiled diapers—is triggered simply by her presence. She holds out hope that things might change as he grows older, but it seems unlikely. The situation worsens when they have a daughter, further straining Eva's relationship with their son, now played by Jasper Newell. He’s not an agreeable person and, as portrayed by Ezra Miller later in the film, he manipulates situations to get what he wants, keeping his mother compliant while feigning camaraderie with his sister. The father may not have considered the implications of giving a young child a toy bow and arrow set, particularly given how seriously "Kevin," identifiable by the tattooed words “malevolent” on his forehead, takes up the hobby. You sense that things will end badly, though perhaps not as terribly as they do in the final scenes. Miller’s performance is notable; he brings a calculated quality to his depiction of this troubled character. He and Swinton have a strong rapport, her mounting frustration becoming increasingly evident as she reaches her breaking point repeatedly. The story unfolds through a retrospective format, hinting at a terrible event but requiring viewers to follow the narrative thread to understand how it came about. Dialogue is sparse, echoing countless parental interactions with children who struggle to communicate—interactions that sometimes inspire thoughts of simply abandoning them. It’s an unsettling film, though not gratuitously so. The lasting impact comes from Newell, Miller, and Swinton's creation of a psychologically intense atmosphere that is genuinely chilling.

Source on TMDB