An autistic boy appears to be the only witness to a murder. Because of the boy's inability to communicate with others, a child psychiatrist must work with the child to solve the crime. I presume that the film's "take" on autism is at least reasonably accurate. But, as a murder mystery, the film was a disappointment. There just isn't that much to the story, which contains large amounts of filler. The plot is contrived. And the film's pace is very slow.
One gets the impression that the real purpose of the film is to "teach", or tutor, viewers on the subject of autism. I have no problem with that, except that by using a vulnerable child as a major character, the film becomes manipulative, in that it uses the child to invoke a sympathetic response from viewers.
The film's music, costumes, and production design are fine. Ben Faulkner, as the little boy, does a fine job in a difficult role. Other actors also give credible performances. But Richard Dreyfuss, as the psychiatrist, is dreadfully miscast. An older actor with a more refined persona would have been more believable.
If you have an interest in autism, "Silent Fall" is worth watching. And the film does have moments of suspense, especially toward the end. But the film lacks the complexity and depth to be a truly entertaining whodunit.