That's right: It's time to meet a certain gingham-clad teenager, one who just took an express cyclone to Oz. (Noticeably absent: Her little dog, too.) Her name, of course, is Dorothy Gale -- and though her big landing doesn't flatten any members of Glinda's sisterhood, Zelena is immediately suspicious of the girl. (First sign something's amiss: Why isn't she wearing braids?)
For awhile now, the Witch of the West has been operating under the assumption that she's the subject of a grand prophecy -- one that proclaims a great sorceress will come to Oz via cyclone and serve as the realm's protector. But Dorothy also hitched a ride to Oz on a whirling windstorm -- meaning that she, not Zelena, might be the witch who was foretold. Meaning that Zelena's new family -- the one thing she's been longing for her entire life -- might be snatched away as quickly as it appeared. Meaning that the jealous green tinge that vanished from Z's skin as soon as she turned over a new (less green) leaf is already starting to come back.
Short story shorter: Zelena discovers that according to a bit of prophecy Glinda never told her, the Cyclone Sorceress is also destined to defeat a great evil. And the witch figures that if the evil foretold is a reference to her own wickedness, she might as well go whole hog. (Cue "No Good Deed.") After her total re-greenification is complete, Zelena meets Dorothy by a well one fateful night. She tries to take out the kid with one of her patented balls of flame, but Dorothy decides to fight fire with water -- and, just like that, Zelena's meltiiiiing! She's meltiiiing! Ohhh, what a world, what a world!!
Of course, getting rid of Z isn't actually that easy. Dorothy leaves Oz with a spring in her step, thanks both to her perceived evil-fighting abilities and the pair of magic slippers she snags from the Wizard himself, newly un-monkeyed by Zelena's defeat. Glinda watches the girl go with a smile -- one that fades as soon as she learns that Zelena is actually very much alive. The Wicked Witch faked the whole melting thing to get Dorothy the hell out of Oz. But even though she's banished her rival to Kansas, Zelena won't be content to take her old seat at the coven's tea table. Instead, she's determined to change her past after all... and as the Storybrooke portion of the evening begins, Z is just about ready to finally put that plan into action.
NEXT: Head into the light, Regina!