Having read the book, I feel the film did justice to the novel and the story, though perhaps not to the characterisation of Mr Stevens.
We spend time with Mr Stevens whilst he is driving through the English countryside on his way to meet Miss Kenton. He has received a letter from her and circumstances have enabled him to both find a professional reason for meeting her and the opportunity to travel. We are privy to his recollections of his career and his relationship with Miss Kenton. The novel speaks of how we chose to live our lives and decisions we believe whole heartedly are the correct and moral ones, but which turn out to be misguided, or not what they seemed.
I don't recall reading anything before where I completely believe the ideas put forward by the character are those of the character, and are not those of the author using the character as a conduit. It is an incredible thing to be able to create people who exist as a whole, only barely removed from reality. Ishiguro is a phenomenal writer, it is him who seems to be the fiction.