Sam and Dean accidentally free Dorothy, who has been trapped in the bunker for years, who seeks their help in killing the wicked witch.
Did You Know?
The episode references the book The Wonderful Wizard of Oz by Frank Baum as being a coded telling of the 'real' Dorothy's adventures. However, when the Wicked Witch's shoes are shown, they are ruby as in the 1939 movie, and not silver as they appeared in the book. (The movie's creators changed them to take advantage of the new Technicolor film process.) See more
[to the Wicked Witch
What's the matter, darling? Cowardly Lion got your tongue?