Finishing TreeStory tests don't seem to work properly?

Please enter a story line 

(Enter a sentence with placeholders, i.e.: Thanks __name__ for helping me out.:  
Please enter a(n) first prompt:  java.lang.NullPointerException
    at com.teamtreehouse.Prompter.promptForWord(Prompter.java:99)
    at com.teamtreehouse.Prompter.promptForWords(Prompter.java:58)
    at com.teamtreehouse.Prompter.run(Prompter.java:38)
    at com.teamtreehouse.Main.main(Main.java:15)
    at JavaTester.run(JavaTester.java:77)
    at JavaTester.main(JavaTester.java:39)

package com.teamtreehouse;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;


public class Main {

    public static void main(String[] args) {
        Prompter prompter = new Prompter();
        String story = prompter.promptForStory();
        Template tmpl = new Template(story);
        prompter.run(tmpl);
    }
}

package com.teamtreehouse;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.*;

public class Prompter {
    private BufferedReader mReader;
    private Set<String> mCensoredWords;

    // Console console = System.console();

    public Prompter() {
        mReader = new BufferedReader(new InputStreamReader(System.in));
        loadCensoredWords();
    }

    private void loadCensoredWords() {
        mCensoredWords = new HashSet<String>();
        Path file = Paths.get("resources", "censored_words.txt");
        List<String> words = null;
        try {
            words = Files.readAllLines(file);
        } catch (IOException e) {
            System.out.println("Couldn't load censored words");
            e.printStackTrace();
        }
        mCensoredWords.addAll(words);
    }

    public void run(Template tmpl) {
        List<String> results = null;
        try {
            results = promptForWords(tmpl);
        } catch (IOException e) {
            System.out.println("There was a problem prompting for words");
            e.printStackTrace();
            System.exit(0);
        }
        String storyResults = tmpl.render(results);
        System.out.printf("Your TreeStory:%n%n%s%n%n", storyResults);
    }

    /**
     * Prompts user for each of the blanks
     *
     * @param tmpl The compiled template
     * @return
     * @throws IOException
     */
    public List<String> promptForWords(Template tmpl) throws IOException {
        List<String> words = new ArrayList<String>();
        for (String phrase : tmpl.getPlaceHolders()) {
            String word = promptForWord(phrase);
            words.add(word);
        }
        return words;
    }

    public String promptForStory() {
        BufferedReader br = new BufferedReader(mReader);
        String story;

        System.out.println("Please enter a story line \n\n" +
                        "(Enter a sentence with placeholders, i.e.: Thanks __name__ for helping me out.:  ");
        try {
            story = br.readLine();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return story;
    }

    /**
     * Prompts the user for the answer to the fill in the blank. Value is guaranteed
     * to be not in the censored words list.
     *
     * @param phrase The word that the user should be prompted. eg: adjective,
     *               proper noun, name
     * @return What the user responded
     */
    public String promptForWord(String phrase) {
        BufferedReader br = new BufferedReader(mReader);
        String mPhrase = phrase;
        boolean isInvalidWord = false;
        String word;
        do {
            System.out.printf("Please enter a(n) %s:  ", mPhrase);
            try {
                word = br.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            for (String censoredWord : mCensoredWords) {
                isInvalidWord = word.equalsIgnoreCase(censoredWord);
//                System.out.println("\n\n" + mPhrase + " " + isInvalidWord + " " + word);
                if (isInvalidWord) {
                    System.out.println("That language is not allowed. Try again. \n\n");
                    break;
                }
            }

        } while (isInvalidWord);

        return word;
    }
}