1 Once upon a time
The season starts with Emma’s family and friends trying to find a way to get her back after she was taken by the darkness and against their better judgment they turned to Zelena for help. Zelena, the wicked witch, has agreed with her own ulterior motives only to be disenchanted by Regina, who uses Zelena's magic to enact the Apprentice's wand which creates a portal that brings everyone to the Enchanted Forest. When they found Emma, she was confused trying to find the powerful wizard Merlin while being guided by a spirited Rumpelstiltskin, who is encouraging her to embrace her darkness and make her task easier. After their meeting with King Arthur in their quest towards Camelot, they all woke up in Storybrooke with no memory of the past six weeks of their time in Camelot, but they do remember going there. They meet Emma, who is now the Dark One and is vowing vengeance on them all.
2 Once Upon a Time
The episode starts by showing us some of what happen in Camelot in the Story Brooker’s missing six weeks. The Story Brooker’s are seeing in Camelot trying to keep Arthur and the Arthurian from revealing their true identities and prevent Emma from going dark as they search for Merlin. Which leave Regina pretending to be The Savior in order to save and keep their attention away from Emma. However, Regina is the Evil queen, so their plan was short lived as Percival recognizes Regina at the ball Arthur held in their honor and alerted Arthur leading to Robin getting stabbed with Percival's sword and David killing Percival. With Robin bleeding to death in the morning Regina asks Emma to save Robin despite Hook's plea not to, but Emma saved him, and it resulted in Regina paying the price.
Meanwhile in Storybrooke, the residents, and newly transported Arthurian's, are becoming fearful of Emma as the Dark One, and Regina is paying the consequences of Emma saving Robin’s life as per her request and must step up when a demon called the Fury attempts to take Robin's soul as payment. Hook is struggling with Emma being the dark one, and Henry meets a girl he liked instantly named Violet. It is revealed that the Excalibur sword was brought back in stone to Storybrooke by the Dark Swan, but she can't pull out Excalibur to make it whole unless she pays the price.
3 Once Upon a Time
In Camelot, the mission to free Merlin continued and everyone played their part. David accompanies Arthur to The Forest of Eternal Night to obtain a mushroom called the Crimson Crown that would allow them to communicate with Merlin. King Arthur later makes David a Knight of the Round Table and told him to take his place at the Siege Perilous seat. Meanwhile, Mary Margaret stepped outside to attend baby Neal and ran into Lancelot who told his old friend that the dangerous villain in Camelot is not Emma but Arthur because Camelot is not what it seems. Back in Storybrooke, King Arthur's true intentions are revealed when Arthur's jailed squire tells him that he did everything that was asked of him to deceive David into believing that he had stolen key items, which is all part of Arthur’s plan to turn Storybrooke into the "New Camelot." Arthur asks his imprisoned squire to drink poison so others can't use magic to make him talk. Emma sends Hook a message to meet her on his ship. Hook questions Emma about what she had behind the locked door in her house but she evades the question and try to make a move on Hook. Hook rejected her knowing that she needs something and moments later, Emma disappears in a wisp of blackness.
4 Once upon a time
The episode begins in Camelot's before the Story Brooker’s arrived, with Arthur's obsession with Excalibur taking a toll on is marriage to Guinevere, which leads to her to go behind his back with Lancelot as the two seek out the dagger only to be confronted by Rumpelstiltskin. Rumpelstiltskin offers Guinevere a deal she couldn’t refuse and ends up paying the price for it at the hands of Arthur. A five years jump bring us to when Arthur learned that Emma was the Dark One from David and Mary Margaret discloses that Lancelot is still alive. David and Mary Margaret's plan to save Emma and help Lancelot is obstructed with Arthur arresting Lancelot and using Guinevere to brainwash David and Mary Margaret into doing his bidding. Lancelot discovers that he was not alone in the dungeon and enlist the help of his cellmate, Merida to take Arthur down. Meanwhile, Hook and Henry tries to keep Emma from giving into Rumpelstiltskin’s manifestations and plan a romantic day for her.
In Storybrooke, Emma tells a reluctant Gold that she has plans to make him a hero and has found the perfect person to help her do the job, Merida. Arthur is up to no good, but David is unaware of that fact. David is blaming himself for Emma being the dark one, but Mary Margaret convinces him that there was nothing he could have done, and reminded him that they are heroes, and they always figure it out.
5 Once upon a Time
In Camelot, Regina and Emma races against time to find the tears of a broken hearted person to complete the spell and release Merlin before Arthur could stop them after Emma discovers how Merlin free from being a tree. Henry tries to prove to Violet that he can be a worthy suitor for her by confronting her father Sir Morgan, but their dinner date did not go as plan, and Henry got his heart broken, which provided the tear they needed to complete the spell free Merlin. After Merlin is free Arthur vows to get even, and Merlin agrees to help Emma get rid of her darkness. Meanwhile in Storybrooke, Emma plans for turning Gold into a hero is on the way, and she sends Gold and Merida in the woods, but after Merida sees how coward Gold was she decided to motivate him and bring out his bravery by using something he holds dear to his heart the cup Belle broken when he first fell in love with her. Henry convinced Emma to help Violet look for her horse. Regina, Hook, Robin, and Belle sneak into Emma's home and discover the Excalibur, and a dreamcatcher, which Regine disclose held Violet's memories, which show that Henry’s heartbreak in Camelot was a part of Emma’s plan to obtain Henry's teardrop. Henry feels betrayed by mother and shut her out of their life and Regina agree with his decision has she also felt betrayed by Emma.
6 Once upon a time
In Camelot, David, Hook, Belle and Merlin break into Arthur’s castle and free Lancelot and Merida. Merida, who is desperate to rescue her brothers, knocks Belle unconscious to enlist her help to save her brothers. Belle wakes as they got closer to the Shores of Dunbroch where they would find the witch’s caldron and use it to locate Merida’s brothers. Merida wants Belle to help change fate, but Belle tries to convince Merida that she can make her own fate. Belle agrees to help Merida with the portion but switch it out as Merida approaches the men who are holding her brothers captive and when she drinks the potion nothing happens. Merida then gained her courage after three arrows were fired at her brothers and she had to fire her own arrow to deflect the one heading for her brother’s head, and she was successful and pulled her sword and demanded they turn over her brothers, and then they bowed down to Merida, their queen.
Meanwhile, in StoryBrooke Emma realizes Gold is willing to fight for Belle, so she orders Merida to kill her. Merida complied with Emma’s request and failed which lead Emma to force her to take the potion that turns her into a bear, and she did and Gold tosses transformation powder into its mouth transforming the bear back into Merida. Emma breaks Zelena out of prison as a part of her master plan, and Emma realizing that Merlin was the usher she met as a child and recalling him warning her to leave Excalibur alone. The heroes realize that Arthur lied to them about being able to contact Merlin and use Henry’s Author abilities to contact him. Henry was successful, and they received a message from Merlin, which reveals that their only hope is someone named Nimue.
7 Once upon a Time
The episode started a thousand years before the age of Arthur; Merlin traversed the desert where he was allowed to drink from the Holy Grail and obtain magical powers and immortality. Eight hundred years later Merlin fell in love with a beautiful woman’s name Nimue who was the sole survivor after her village was burned down by a masked man, Vortigan. Merlin’s love for Nimue clouded is judgment, and he planned to forge the enchanted chalice into a sword “Excalibur” to cut away this gift so he and Nimue can grow old together. Merlin and Nimue visited her village, and it was in ruins. And with the Dark One questing for the Holy Grail Merlin uses magic to turn the chalice into Excalibur and after he does, Vortigan arrives. Nimue tries to fight him, but she’s not strong enough, and he kills her, but she had drunk from the Holy Grail to achieving immortality and took Vortigan heart and crushed it turning her into the first Dark One leaving Merlin heartbroken. Meanwhile, in Camelot Merlin tells Emma they can make Excalibur whole again but they would need the spark from the Flame of Prometheus, which mean they have to confront the first Dark One, which all ultimate evil spawned. Merlin, however, warns Emma that if they fail in their journey, Merlin will die, and Emma will become the most powerful Dark One ever. Emma and Merlin arrive at the site where Excalibur was forged and broken, and Merlin gave her the dagger to call on the spirits of the previous Dark One, who turn out to be Nimue whose first task is to force Emma to kill Merlin. Emma was able to fight her urges and take the ember and Merlin tell Emma that he kept Excalibur safe by placing it in a stone with his apprentice. The heroes sneak into Arthur’s castle to get Excalibur back.
8 Once upon a Time
In Camelot, Emma is able to save her family and friends from Arthur and Zelena, but Emma’s biggest threat was a spelled Merlin, who is ordered by Arthur to kill her mother, Mary Margaret. Emma pleaded to Merlin to fight the darkness and was able to do so, but Hook received a small cut on his neck when he tried to overcome Arthur and Emma quickly healed him. Emma light’s the Flame of Prometheus, but when she try to forge the dagger with Excalibur, Hook starts bleeding from the neck and collapses. Emma learned that a wound made by Excalibur can’t be healed meaning Hook is dying. Emma was not letting that happen but know that the only way to save him was to create another Dark One, and she used the dagger to remove the darkness from Merlin and tether it to Hook, and he became the second Dark One.
In Storybrooke, King Arthur makes a run for it upon being confronted about his deception and is chased by Hook, but ended with Hook staring down at the wrong end of Arthur’s sword. Arthur attempts to kill him with the sword but is stopped by Emma, who blocks his steel with Excalibur. Emma reveals that the house she’s living in is the one that Hook picked out for them in Camelot, which represents their future together. Emma expresses to Hook that she is fighting for their future leaving him curious, but she can’t tell him how and knocks him unconscious. Zelena delivers a baby girl after an accelerated pregnancy and is taken away by Emma soon after. Zelena and Hook are now chained in her basement where she plans to cut down Zelena after using her as the vessel to hold the darkness. Hook freed Zelena from her bindings and restored her magic, and the two of them escape. Zelena flees the house, but Hook stays behind to get some answers from Emma and found some squid ink and later use it to neutralize her. Zelena reveals to Hook one of Emma's dreamcatchers, enlightening him that he was the second Dark One.
9 Once upon a Time
In Camelot, Arthur and Zelena visit Merida’s home called Dun Broch to find an enchanted helm her father, Fergus, had asked an old witch several years earlier to help him stop invaders from taking over his kingdom. On Merida’s coronation day, the witch interrupts the ceremony telling Merida that she had come to collect the debt left by her father with was for the helm. The Witch gave Merida a day to return, or she would curse her people to live on as bears. After searching the castle Merida tracks down her onetime mentor Mulan for help, but she initiated refuse but decided to help for a price. Merida is disappointed that her father would do such a dishonorable act of using a powered helm to make men fight for him, but she continued on with Mulan, who suggested they return to the witches’ home. They met Ruby “Red” who the witch had turned into a wolf to guard her house, but Mulan realized and used a transformation spell to turn her back human. Zelena and Arthur find the missing helm, but Merida arrives at the same time and shoots a warning arrow telling them that the helm does not belong to them. Merida and Arthur started to fight, and Arthur promises to slay with his sword if she reaches for the helm, but she didn’t have to fight for long because her clan showed up to support her and a sleepy Zelena transports herself and Arthur back to Camelot. The witch returned for the helm, but Merida told her that she intend to destroy it and to her surprise the witch was pleased with the news. The witch explains that finding the helm was a test of maturity left by her father, and gave her a gift in the form of dust that would allow her to talk to her dead father. Mulan and Ruby exchanged stories and seem have developed a friendship.
10 Once Upon a Time
In Camelot, Emma tries to convince Hook that she can get rid of the darkness in both of them, but they will need their families help. Hook and Emma struggle with trusting each other but eventually Emma turned over Excalibur and promised that she will never try to control him again and the two kiss and made up. However the darkness in Hook is controlling him and with Excalibur in his possession wants to take Merlin her and crush it in honor of the original dark one Nimue. Hook took Merlin’s heart and enacted the curse, but Emma was able to stop his curse and by adding dark magic to Hooks’ curse causing a purple explosion in the form of a cloud cover everywhere and then she capture everyone’s memories into a dreamcatcher so they wouldn’t remember that Hook was a Dark One. Meanwhile, in Story Brooke Emma and Henry locate the dreamcatchers but they can’t get to them without magic. Henry removes Emma’s cuff and they later convince the heroes to uses the dreamcatchers to get everyone’s memory back, and after they received their memories back, Emma understands Hook’s plan.
11 Once Upon a Time
Back in the Enchanted Forest, Hook's past with his father abandoning him as a young boy and him killing him when Regina recruits him to kill Cora is revealed. In Storybrooke, as Hook and Nimue prepare to send Emma's and the heroes to the Underworld to allow the resurrected Dark Ones to stay, he reminded of the man he wants to be. Hook realized the possible consequence and turned Excalibur on the previous Dark Ones and asks Emma to sacrifice him with Excalibur, which would save everyone and restore Emma to normal. Emma did as Hook requested sending him to the underworld, but discovered later that Gold used the situation to tether the darkness back into himself, leading Emma to blackmail Gold into helping her bring Hook back from the Underworld. Regina sends Zelena back to Oz after Zelena vows to get sole custody of her daughter.