What would you do if a tree house in your neighborhood could transport you anywhere you wanted to go? Two siblings, Jack and Annie, return to visit the Magic Tree House filled with a magnificent collection of books that can transport the reader to the wonderful faraway settings featured in their pages. As they read a book about knights and the Middle Ages, Annie is intrigued by the Black Knight and the mysterious quest he says one must successfully complete before becoming a knight. When she wishes to visit the castle in the book, the siblings are whisked away to medieval times and set off to learn more about the Black Knight and his quest. Through their adventure, the two discover the power of hope and the true meaning of gallantry.