ABC’s Once Upon a Time season six episode 18 puts Zelena front and center, unveiling a little more about her backstory. Titled ‘Where Bluebirds Fly,’ the episode begins with a teenage Zelena saving a dead baby bird while walking on the Yellow Brick Road. She makes friends with a woodsman named Stanum who believes that if she uses her magic for good, she’s not a monster.
Fast-forward to Storybrooke where Zelena (Rebecca Mader) is preparing a bottle for Robin. She slightly panics when she discovers the crib is empty and the Black Fairy (Jaime Murray) has entered her home and is holding Robin. She’s visiting Zelena because she thinks they can help each other, especially with the upcoming final battle. Zelena tells her she’s not afraid of her and won’t back down, but the Black Fairy insists she should be.
Emma (Jennifer Morrison) and Hook (Colin O’Donoghue) are being all domestic, kissing while making pancakes. Emma admits she’s surprised she’s so happy, and they decide the pancakes can wait as they get more and more amorous. Unfortunately, Snow (Ginnifer Goodwin) barges in without knocking and realizes too late she’s interrupting. Hook’s no longer in the mood and leaves, which is fine with Snow because she’s ready to get down to the business of planning Emma and Hook’s wedding. She’s put together a book with wedding dresses and other crucial material, and Emma gives her a hug for being so excited about her upcoming nuptials.
Wedding planning has to be put on hold as the gang gathers at the sheriff’s station to hear about Zelena’s encounter with the Black Fairy. Regina’s happy that apparently the Black Fairy needs help to win the final battle, and Hook whips out the piece of wood Tiger Lily gave him, telling the gang they need to find its other half to defeat the Black Fairy. Zelena says she doesn’t need a wand because she’s even more powerful than Regina (Lana Parrilla), which sets off a fight between siblings. After being told she’s not taking on the Black Fairy by herself, Zelena leaves in a huff. Regina wants to take the wood to her vault and use a locator spell for the other half, while David (Josh Dallas), Snow, Hook, and Emma are going to get busy with wedding planning at Snow’s insistence.
Rumple (Robert Carlyle) informs Belle (Emilie de Ravin) that Gideon is under the Black Fairy’s control, and Belle’s happy to learn her son isn’t really evil. Unfortunately, the person they need to help them – the Blue Fairy – has been drained of magic and is currently in a coma. Before they can do anything, Rumple has to go to the sorcerer’s mansion to see if there’s a way to restore Blue’s magic.
After Rumple leaves, Zelena barges in and swears the secret of Blue’s being in a coma minus her magic is safe with her since she never liked the fairy in the first place. She’s actually there to ask Belle to babysit Robin for her.
David returns home and finds his front door open. He whips out his gun in case the burglar’s still there, but it’s only Henry who’s busy/preoccupied using his author’s pen. No matter what he writes, it doesn’t alter Emma’s fate. She must fight the final battle. But, what he’s actually trying to do is decipher the symbols he wrote. Henry thought the author’s pen might help, but it doesn’t. David suggests he live life a little, recruiting him to help look at wedding venues.
Back with babysitter Belle, she and Robin are exchanging smiles when Regina arrives. She needs something for a locator spell and she’s not happy to see Zelena’s left Robin with Belle. Belle doesn’t understand what’s got Regina worked up and Regina heads out, obviously angry at her sister.
Back in Oz, Zelena is being waited on by her guards when Stanum, now a man, arrives to ask for help. The Wicked Witch of the North has turned him into tin. He needs to find a new heart before he’s completely transformed into a tin man. He needs her help to get the Crimson Heart which is guarded by a horrible monster. Zelena wants to know what she gets out of this, and Stanum reminds her she wanted to use her magic for good. He’s not afraid of her and even tells her she’s the one who’s afraid and that’s why she acts the way she does. As he’s leaving, Zelena proclaims she’s the most powerful witch in Oz and she’ll prove it by getting the Crimson Heart.
Regina tracks Zelena into the dwarves’ mines where the Black Fairy said she’d be hiding out. Regina tells Zelena she’s stopping her for her own good, and Zelena’s still not over Regina blaming her for Robin’s death after she sacrificed a life with Hades. She’s is, however, over Regina being the one who gets to lecture people, swearing she’s going to take care of this herself. Regina tries to stop her by slamming her into a wall and before Zelena can fight back, the wall begins crumbling.
It looks like Snow’s idea of the perfect wedding venue is Granny’s, but Hook speaks up and says it would be much more romantic to have it aboard the Jolly Roger. Henry brings up the fact half the guests will be seasick, and Hook concedes that’s a good point. Even David isn’t sure about Granny’s, knocking pretty much everything about the place including the fact not all their memories of being there are happy ones. He also reminds Snow that Emma’s a princess and the royal affair will be too big to take place at Granny’s. Snow, unhappy over David’s lack of enthusiasm, tells him to find someplace bigger then, and he says he’s happy too. Oh no…there’s trouble between Snow White and Prince Charming. Henry, Hook, and Emma are confused about what’s going on, but follow Snow and David on their hunt for a bigger venue anyway.
Regina and Zelena are now trapped after the rocks closed off their exit. Even in this position, they can’t stop arguing. Regina is positive they need the wand to defeat the Black Fairy. Zelena fires back, telling her sister that although she and Emma might need a fairy wand, she doesn’t. Regina wants to know why being better than everyone else is so important, and Zelena says it’s because she is.
Back in Oz, Zelena and Stanum look for the monster, and Stanum tries to tap into Zelena’s humanity. He tells her she can drop the act; he knows what she’s really like. He’s positive she was bored all alone in the castle and she’s happy to be out in the woods with an old friend. Just as he’s about to offer up a suggestion for what she should be working on, a lion attacks and drags him away.
Regina chases Zelena through the mines but they both stop when she sees a vein of fairy crystals. Regina and Zelena wonder what the Black Fairy could possibly want with light magic, and of course that’s when she and Gideon show up to provide some answers. Gideon knocks Regina across the room and Zelena tells the Black Fairy she’s there to kill her.
While Regina goes after Gideon, Zelena chases after the Black Fairy. They end up in a chamber of fairy crystals and Zelena uses her magic but the Black Fairy only laughs. She’s easily able to stand up against Zelena who has fallen into her trap. The Black Fairy uses Zelena’s magic to weaponize the crystals with dark magic while Gideon has Regina under control. The Black Fairy taunts Zelena and then explains she’s done all this in order to start the final battle. But, she promises Zelena and Regina won’t be around much longer to witness it.
Back in Oz, Zelena confronts the lion, telling him she’s the king of the forest. He dodges her magic and attacks, landing on Zelena’s chest. Stanum launches an axe at him, distracting him enough for Zelena to get on her feet. It works, and Zelena changes the lion from a beast into a coward. Stanum doesn’t have much time left and they resume their trip through the woods in search of the Crimson Heart.
Zelena and Regina appear back above ground, and Zelena wants to go back into the mines to get some of the dark fairy dust to use against the Black Fairy. Regina’s upset and blames all of this on Zelena, telling her she should just go back to Oz where she can be on top and won’t worry about having to prove herself ever again.
Back to the wedding planning we go and the group is now at town hall which Snow believes would be perfect for the wedding. David’s not sold on this place either, and when Emma jokingly says he probably won’t be happy unless they host it at his castle in the Enchanted Forest or at Excalibur in Vegas, David seizes on the castle idea. He asks how many beans it would take to get everyone back there, and Snow is beside herself. She asks to speak to him outside and demands to know what’s really going on. David wants to know why they’re rushing into this, swearing his reluctance isn’t about Hook. The truth finally comes out. Their wedding day went from the best day of his life to the worst with the arrival of the Evil Queen. He doesn’t want Emma to have that same experience and with the final battle about to go down, he doesn’t think now is the right time for the wedding. He wants Emma to only be thinking of her life ahead and not about the Black Fairy. Snow’s worried they won’t be around to witness that – and that Emma might die before saying I do – but David swears they will live through this battle. They have to have hope. Emma, Hook, and Henry overhear and Emma agrees with her dad. She and Hook want to postpone the wedding until it’s absolutely the right time.
Zelena picks up Robin from Belle, and Belle says she’d watch her anytime. Zelena says that won’t be necessary as it’s time for them to head home.
Zelena cradles Robin and walks through the snow. She stops, looks back at the town, and uses the dark fairy dust to create a green tornado to take her to Oz.
Another flashback to Oz shows Zelena and Stanum approaching the Crimson Heart. She removes it from its case and tries to place it in Stanum, but all it does is drain her magic. She believes Stanum’s set her up, but he tries to convince her he had no idea this would happen. Zelena accuses him of working with Dorothy and he swears he doesn’t know anyone named Dorothy. He also tells her she just need friends – not a time-travel spell – to not feel alone. The tin takes over more of his body and as it covers his face, he warns Zelena if she leaves him there to rust she’ll be alone for a very long time. “That’s a risk I’ll just have to take,” she replies. He can’t move and she grabs the box with the heart, reminding him magic is what made her special. As she’s leaving, she says maybe Dorothy will come by and save him.
Regina catches Snow, David, Hook, Emma, and Henry up on what Zelena caused down in the mines. She also reassures them Zelena won’t be a problem anymore. As Regina’s explaining the Black Fairy created the dark crystals to start the final battle, Zelena and Robin enter the room and no one seems happy to see them, especially not Regina. Zelena says she changed her mind about returning to Oz because everyone there hates her. Zelena tells Regina’s she’s all she’s got, but she thinks she can help. Since the Black Fairy used her magic to turn the crystals dark, she’s tethered to it and can destroy it with the Crimson Heart. If she uses it, it will destroy all of her magic!
Another flashback to Oz and Zelena sits down at her dinner table, obviously regretting her decision to leave Stanum to rust.
And now we’re back in Storybrooke where Regina and Emma accompany Zelena as she opens the box containing the Crimson Heart. She makes Regina promise to look after Robin if something happens. Emma also promises, saying they’ll protect Robin with their lives. Zelena picks up the heart and it begins draining her of all her magic. It works and the dark magic is gone from the fairy crystals! Zelena is fine but weak, and Regina assures her she’s never looked stronger. Regina gives her sister a hug, telling her she’s never been prouder of her. The next step is for them to get Mother Superior to ask the dwarves to mine the crystals, but Regina says she hasn’t been able to reach her. Zelena spills the beans that Rumple has her.
Emma, Zelena, and Regina visit Rumple and Belle, and they both apologize for what happened to Mother Superior. The threesome explain they’re there to help wake the Blue Fairy, and Rumple agrees to let them try. Emma crushes a crystal over Blue and her heart starts beating again.
The Black Fairy watches all this through a crystal ball. Gideon asks if she’s afraid they’ll find the missing half of the wand, and the Black Fairy admits that’s not why she wanted the Blue Fairy to be out of the picture. It turns out Blue knows her darkest secret…the real reason she gave up her son.