Empty Xml Document response from Api

I need information from imdb unoffical api "omdbapi".I am sending link in correct but when I get response the document is null.I am using htmlagiltypack.what am I doing wrong?

here is direct link:http://ift.tt/1u11gow

        string url = "http://ift.tt/1c8P6Bo" + ImdbID + "&plot=short&r=xml"; 
        HtmlWeb source = new HtmlWeb();
        HtmlDocument document = source.Load(url);