The specifics of what occurred aren't revealed at first, but it becomes apparent that a father, portrayed by Benedict Cumberbatch, and his two young sons, Henry and Richard Boxall, are dealing with the aftermath of their wife’s/mother’s death. The dad is attempting to maintain a positive outlook as he tries to encourage his children both at home and in school while also continuing his job creating animation for an older audience. A disturbing atmosphere develops within their house when he begins experiencing unsettling sounds and visions, and a crow that he's been drawing appears to be connected to these occurrences. While the viewer can readily understand the significance of this bird—particularly in its more upright and vocal form—the character remains unaware as the film unfolds through chapters focusing on the father, the sons, and even the bird itself, examining the idea and profound effect of grief. The two Boxall boys perform their roles admirably, but it's Cumberbatch’s exceptional performance that truly makes the movie worthwhile. His portrayal depicts a man struggling to process his loss; while he isn’t uncaring toward his family, his efforts to suppress his emotions, protect his sons from the intensity of his despair, and lose himself in professional work aided by Scotch are powerfully conveyed by an actor who seems genuinely overwhelmed. The depictions of the birdlike figure introduce considerable psychological tension, even violence, which further contributes to the frustration felt by this man and, to some degree, his sons—they’re old enough to grasp that something terrible has happened but not yet understand its lasting consequences. The musical score also adds a compelling sense of sadness and agitation at times, and I was honestly quite surprised by how invested I became in this family's situation as the story progressed. Perhaps it isn't ideal viewing for those recently experiencing grief, but otherwise, it offers a unique perspective on the subject and is worth seeing.

Source on TMDB