Zelena wants to put an end to the Black Fairy's reign of terror on Once Upon A Time Season 6 Episode 18 "Where Bluebirds Fly."
Unfortunately, Regina's not as excited about the prospect as her sister. But will the sisters come together in the end with an unstoppable plan?
Judging by the photos below, the Black Fairy's hatching her own scheme. She's summoned Gideon to the well for a late night powwow.
We're also getting a look at another infamous member of the Oz family.
Scroll through the photos below and tell us your theories! Will Zelena succeed? Can Gideon stop his grandma?
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Who's There? - Once Upon a Time Season 6 Episode 18
We have ourselves an Oz flashback! Or at least a flashback to a time when Zelena was feeling her greenest. What does the Wicked Witch see lurking in the shadows?
Tin Man, is that You? - Once Upon a Time Season 6 Episode 18
Sure, he could be a regular knight. But it certainly looks like we're traveling through Oz this week. We've already met the wizard/flying monkey, and Dorothy, too. What twist will the Tin Man bring?
Simply Wicked - Once Upon a Time Season 6 Episode 18
Zelena promised wicked would always win. But our favorite witch hasn't had the best of luck with her evil plans. Something's put this unhappy look on her face. How will she get revenge?
Friends or Foes? - Once Upon a Time Season 6 Episode 18
Once Upon A Time loves putting its own spin on fairy tales. Maybe the Wicked Witch and the Tin Man were destined to be the best of friends. It could happen!
Zelena's Frightened! - Once Upon a Time Season 6 Episode 18
What does it take to frighten the Wicked Witch? We shudder to find out. But if we had to guess, anyone harming her daughter would be a safe bet. What terror lurks outside?
Anticipating the Worst - Once Upon a Time Season 6 Episode 18
We can't blame Zelena for assuming something bad is about to happen. Even though she's done more than her share of wicked things, we can't help loving her. Her fear is our fear, too.