-You need to check if the movie is present; 
-If you have a look in a binding.pry on line 15 you will see that API will return a hash with key of 'Error' and a value of 'Movie not found' if the movie is not present; 
- You need to check for an error and if its present store it in a variable; 

        if params[:movie_title]

        url = "http://www.omdbapi.com/?t=#{params[:movie_title].gsub(' ','+')}"
        response = HTTParty.get url
        @movie = JSON(response)

        if @movie['Error']
            @movie_error = @movie['Error']
        else
            @movie_title = @movie["Title"].upcase
            @movie_cast = @movie["Actors"]
            @movie_poster = @movie["Poster"]
            @movie_plot = @movie["Plot"]
            @movie_time = @movie["Runtime"]
            @movie_director = @movie["Director"]
            @movie_genre = @movie["Genre"]
            @movie_year = @movie["Year"]
            @movie_awards = @movie["Awards"]
        end
    end