"Birth" is the eighth episode of the fifth season of the American fantasy drama series Once Upon a Time, which aired on November 15, 2015. The episode serves as the first part of a 2-episode airing night that were unrelated, with the second part being "The Bear King".
In this episode, Emma saves her parents, Regina, Hook, and Robin from King Arthur and Zelena. In Storybrooke, Hook and Zelena become allies.
Plot Opening sequence The emerging new Dark One from the vault appears in the forest.
Event chronology The Camelot scene at the mes place after "Nimue" and before "Broken Heart". The Enchanted Forest and Storybrooke events take place after "Nimue".
In the Enchanted Forest, outside Camelot Three weeks earlier in Camelot, Emma brings a box with the Spark of the Promethean Flame in it to Granny's Diner, and she tells Henry that she can reunite the sword with it. Henry tells her that the others are not back with Arthur's fragment of Excalibur, and Emma says that Merlin is missing too. Granny and Henry begin to lock up the shop, but before they can finish, they are frozen with magic by Merlin, who is there and being forced to follow Arthur's orders, due to him being tethered to the Excalibur fragment. He says that Arthur tethered him to Excalibur and has ordered him to unite the sword, with the Promethean Flame. Emma refuses to hand it over, and Merlin says that Arthur has her family and will force him to kill them unless she hands over the Dagger of the Dark One and the flame. Emma says that it's not a flame yet, just a spark since she hasn't had enough time to light it yet, but Merlin tells her that with her power, she will be able to light it when she's ready. Emma then says she can't give up without a fight. But Merlin tells her that "acceptance is a form of strength," begs her not to seek vengeance and not to make the same mistakes as Nimue.
Emma tries to ignite the spark into a flame when Rumplestiltskin's manifestation appears and says that Arthur will kill her if he reunites Excalibur, but she says she has no choice and can't risk the lives of her family. Rumple's manifestation says that she can only light it when she's ready to give up the darkness. As the manifestation tries to goad Emma into lighting the flame, Emma loses her temper and yells at him to stop. Henry finds Emma talking to herself, and he asks what she's doing, and what the "voices" said. Emma says that they told her she wasn't ready to give up the darkness. He shows her a photo of a house that he and Hook were looking at for their Operation Light Swan, which Hook planned to obtain for Emma after she was free of the Darkness. Henry tells her that it was a reminder of something she could look forward to. Emma shuts the lid on the spark and says that she's not ready to give up the darkness just yet because she has to use her dark magic one more time.
Emma goes to the woods and sees Arthur, Merlin, and Zelena, with Emma's family tied to trees. She tells him to free them but Arthur wants Emma to hand over the dagger, and spark or else he'll "unleash" Merlin, and brought along Zelena to make sure she complies, asking Emma if she should kill Hook or David first. Emma hands Zelena the spark but when she opens it Zelena discovers that it's a fake, containing a spell that binds her to a tree. Furious that Emma tricked him, Arthur orders Merlin to fight her, and they battle by using magic. Merlin says he wishes Emma could defeat him, but that he's too experienced, and Merlin knocks her back. Arthur, believing he has the upper hand, orders Merlin to kill Mary Margaret, which he does by choking her with one of the tree's vines. Emma then pleads with Merlin to fight back against Arthur, telling him that he is the greatest sorcerer of all time and that if he can't fight off the darkness, no one can. Merlin struggles, but successfully fights off Arthur's control and stops the vine from choking Mary Margaret.
Arthur is stunned but continues trying to force Merlin to kill Mary Margaret, pushing Merlin to the limit, but the distraction gives Hook time to free himself and come at Arthur. After a brief scuffle, Hook knocks the sword away from Arthur and keeps him from grabbing it. Arthur runs off and releases Zelena, who teleports both of them away. Emma thanks Hook and heals a cut on his neck from Excalibur. He says that now they have the sword, so they just need to light the spark, and then they can get the darkness out of Emma. Back at Granny's, Hook recounts the adventure to Henry, who is excited. David and Regina report back that Arthur has retreated far away and Emma is outside with the spark, trying to make it work. Regina comes out and she tells her that Rumplestiltskin's manifestation is playing with her, telling her she can't light it because she's not ready to give up the darkness since she is still lured by it, even though she knows that it's wrong. Regina grabs the dagger and commands Emma to tell her why she's afraid to give up the darkness. Emma says that she can't protect her family if she does. Regina says that's not the truth, that it's only "a wall," and uses the dagger to continue probing her, trying to get her to admit the truth. Hook, David, and Mary Margaret come up, and Hook snatches the dagger from Regina, thinking that she's worsening the situation, while Emma storms off with the Dagger and the spark. Regina responds by telling them that she wasn't being cruel; she was trying to help her find the truth, even it is painful.
Hook finds Emma and tells her that he's sorry that Regina used the Dagger on her, but Emma says that Regina was right and that with her help, she was finally able to uncover the truth. She shows Hook the ad for the house and says that she's afraid of the future. He asks if she's scared to move in with him and Emma tells him that "it’s everything." She says that she's afraid because she does want a future with him, and the minute the darkness is gone, that future begins. Hook says that's music to his pirate ears. He tells her not to be afraid of the future and kisses her. The Promethean Spark ignites, and Hook points out that now that Emma has overcome her fear, they are finally ready to reforge Excalibur.
Back at Granny's, Emma takes part of the Promethean Flame and ionizes it, before she thrusts both halves of Excalibur into the flame to reunite the blade. However, the cut from Excalibur that Hook received reappears, causing him to bleed and collapse. Emma catches holds him and tells him that she's not ready to let him go, but Hook tells her that it's okay and wants to see her reunite Excalibur before he dies. As Emma desperately searches for a way to save Hook, Merlin tells her that there's nothing she can do to heal a wound from Excalibur (which was forged to cut immortal ties), and Regina and Emma's parents tell her that Merlin's right. However, Emma yells that after how hard Regina pushed for her to save Robin, it was not fair for her to give up Hook, and says that Merlin was lying, that she could use her power to save him. Emma says that she could release Merlin from the fragment of Excalibur and tether Hook's life to it instead; but Merlin says that if she does, it could create another Dark One, which will multiply the Darkness so much that Emma will be unable to destroy it unless she pays "the steepest of prices." He also tells her that such an act will complete her fall into the darkness. However, Emma says that she won't let Hook go and uses her magic to take both of them to a field of Middlemist flowers.
In the field, Hook says that he doesn't want to become a Dark One, that he's weak, unlike Merlin and Emma, and that he'll succumb to the darkness again if she does that. Emma says that he won't, that she'll help him fight it together, and that she still wants a future with him. But Hook tells her not to, that their future is now, and that he's happy just to know that she has one, before going limp. Emma says that it's not enough for her. She holds him and cries, and then takes Excalibur and floods it with magic. In the diner, Merlin tells them it's too late, and tendrils of darkness emerge from him as he is released from Excalibur (the darkness was what bound Merlin to the fragment of Excalibur). The dark tendrils re-emerge from Excalibur and flow into Killian's heart, bathing him in a golden light. Then, Hook vanishes and his name appears on the blade of Excalibur. Then, a burst of dark magic erupts from the blade of Excalibur, turning Emma into her present-day appearance, with white hair and a dark appearance, signifying the completion of her journey into darkness. At the same time, a flood of dark energy pours into the entrance of the Vault of the Dark One, and reforms into a cloaked Killian.
In Storybrooke In the woods, David, Hook and Robin are ready to confront Arthur at his tent, and they brought weapons along, just in case. Robin and Hook secure the area while David goes inside the tent. As Arthur greets David cordially, David demands to know why Arthur lied and tried to burn the Crimson Crown, and tells him about the message they received from Merlin, which detailed that only Nimue could destroy that Darkness. David demands to know who Nimue is and points his gun at Arthur. Arthur, however, decides to throw the threesome off with a table, then escapes into the wood with the three in pursuit. After Arthur trips, he sees Hook and kicks him down and draws his sword on him, but just before he can kill Hook, Emma suddenly shows up and uses the now-reunited Excalibur stop Arthur's attack, telling a stunned Arthur that the sword no longer controls anyone, before sending him flying into a tree. Hook thanks Emma, but Emma says that there's no need to. Hook apologizes for what he said on his ship, and when Emma asks if he meant that he didn't love her and that he refused to accept who she now was, he says that he still does and will always love her. When Emma asks Hook what he wants, he says that he wants to help her, and asks who Nimue is. She says that Nimue doesn't matter anymore, and that it will all be over tomorrow. Hook asks why she needs the sword. Emma walks away and Hook says he knows she has reasons for doing this, and Emma tells Hook that she does, and that she's doing all of this for him, before disappearing.