original: The film is mainly based on Robert Drewe's book Our Sunshine.
simplifications: The film is based on Robert Drewe's book Our Sunshine. The film's based on Robert Drewe's "Our Sunshine". The film is based on a book called Our Sunshine. It was written by Robert Drewe. The film is based on Robert Drewe's book Our Sunshine. The movie is based on Robert Drewe's book Our Sunshine. The book "Our Sunshine" written by Robert Drewe inspiried the movie. The movie is based on the book Our Sunshine. The film is based on "Our Sunshine". "Our Sunshine" is a book by Robert Drewe. The film is based on the book Our Sunshine by Robert Drewe. The film is mostly based on Robert Drewe’s book, Our Sunshine.