“Once Upon a Time” viewers received a bombshell in episode 3 of Season 5 -- King Arthur (Liam Garrigan) has ulterior motives and is not the man he says he is. Lancelot (Sinqua Walls) revealed the truth to Mary Margaret (Ginnifer Goodwin), but what will she do with that information? It all played out in episode 4, “The Broken Kingdom.”

Camelot Of The Past

A flashback many years ago explains to fans of the ABC fairy-tale drama that Merlin (Elliot Knight) has been trapped in the tree since before King Arthur was a young boy. When Arthur was just a child, the tree revealed the prophecy that he would one day remove Excalibur from the stone and make Camelot whole. Although he was mocked when he was younger, he eventually did find the sword and pulled it from the stone. However, Excalibur wasn’t whole.

Instead of revealing to the people of Camelot that he only had half of the sword, he hid the broken piece from his subjects. His wife, Guinevere (Joana Metrass), knew something was wrong. When she questioned Arthur, he explained his quest had only just begun -- he needed to make Excalibur whole.

Over the next five years Arthur became obsessed with finding the Dark One’s dagger. He studied page after page, but couldn’t decipher where the blade was hidden. Eventually, his quest took a toll on his marriage. On Guinevere’s birthday, she begged her husband to join her at the party. However, Arthur remained hidden away with his notes. Lancelot was there for his queen as a friend and confidante, but she needed her husband. When Arthur finally emerged and revealed that he had found the dagger a days ride away, he left Guinevere behind with Lancelot to protect her.

Once Upon a Time Lancelot Lancelot's (Sinqua Walls) job was protecting the queen of Camelot in Season 5, episode 4 of "Once Upon a Time." Photo: ABC

Guinevere had no intention of being left behind though. She broke into Merlin’s tower and found a magical gauntlet that would lead her to the dagger. Lancelot found her before she tried to make her escape. But instead of preventing her from going, he decided to join her in the quest.

The two ended up at the vault of the Dark One, the same vault that Emma (Jennifer Morrison) emerged from in the Season 5 premiere. A staircase brought them underground, but they didn’t make it that far. A dark cloud attacked Lancelot, forcing Guinevere to fight off the darkness. She succeeded, and celebrated the victory by kissing Lancelot.

“I was sure I’d lost you,” she told Lancelot. However, after the kiss she apologized and promised that it would never happen again. Lancelot agreed, and the two moved forward with their quest -- to help their king.

They eventually found a doorway that led them into another world. And right beyond that door was the Dark One’s dagger. It was not as simple as just taking the blade though. A force field knocked both Guinevere and Lancelot back when she tried to grab it -- and Rumplestiltskin appeared.

Of course, Rumplestiltskin had no plans to let the two make off with his dagger. But he was very interested in Guinevere’s gauntlet. He made Guinevere an offer for the “next best thing” -- enchanted sand from the Island of Avalon. The enchanted sand could fix anything -- even Excalibur. Although Lancelot told Guinevere not to take the offer, she traded with Rumplestiltskin.

The two successfully emerged from the vault, but Arthur caught Lancelot and Guinevere being a little too affectionate with each other when departing. When he confronted his wife, Guinevere denied that anything was going on between the two. Instead, she explained about how she went on a quest with Lancelot to get the dagger to bring back the man she loved. She revealed although she found the dagger, she brought back the enchanted sand to trick him. However, she realized she didn’t want to use.

Guinevere wanted her husband to make a choice -- their marriage and the kingdom of Camelot or completing the sword. She threatened to “follow her heart to where it belongs,” which is when King Arthur grew angry. He accused her of being in love with Lancelot and decided to steal the magic sand and use it on her. The sand “fixed” their marriage and made her supportive of Arthur’s quest to complete the sword. And Arthur wasn’t done there. He used more of the sand to fix the broken Kingdom of Camelot and make it whole.

Storybrooke’s Invasion Of Camelot

Meanwhile years later, King Arthur shares with David (Josh Dallas) that the sword is broken. He explains that he needs the dagger of the Dark One to make it whole, and David is just the man to help him find it. But what would make David help him? King Arthur claims that with the dagger they wouldn’t need Merlin to destroy the Dark One because Excalibur whole has the “power to destroy the darkness once and for all.”

David is willing to do whatever it takes to help Emma, who is slowly getting worse. She stays in her room whittling away and making dream catchers. However, she can’t stop the voices in her head. They lead her to the dagger, which Regina (Lana Parrilla) has hidden away in a cabinet. But Regina is wise enough not to leave the dagger unprotected. When Emma tries to reach for it, a magic spell prevents her from taking it. Her vision of Rumplestiltskin (Robert Carlyle) encourages her to use her magic to break the spell, but Emma turns the magic on her hallucination. Of course, Rumplestiltskin isn’t real so the magic goes right past him. It does almost hit Hook (Colin O’Donoghue) though.

Emma falls silent and lethargic. With time running out, David wants to give the dagger to King Arthur. But Mary Margaret tells her husband about Lancelot and how their old friend said they couldn’t trust Arthur. The two get into a huge fight, unable to come to agreement on what to do. David ultimately comes to his own decision to bring the dagger to King Arthur. Unfortunately for David, Mary Margaret gets to it first. The dagger is missing when David opens the box. King Arthur is confused until David fills him in on Lancelot’s return.

Meanwhile, Henry (Jared S. Gilmore) brings Emma and Hook to a barn that belongs to Violet’s (Olivia Steele-Falconer) family. Emma and Hook hide out in there while Henry’s crush takes him out horseback riding. It’s there that Emma finally comes clean to Hook about her visions of Rumplestiltskin.

To help Emma, Hook takes her horseback riding to get her mind off of the darkness. He explains that he too once suffered from hallucinations, but that sailing on the Jolly Roger helped him.

“I’ll never stop fighting for us,” he tells her. “All you have to do is trust me.”

Emma does, and Hook takes her to a field full of flowers. It’s there that Emma discovers she’s finally free of Rumplestiltskin for the first time since she arrived in Camelot.

Cut back to the other heroes. It turns out Lancelot is hiding out at Granny’s. Mary Margaret goes to him and tells him they must hide the dagger. And Lancelot knows just the place! He brings Mary Margaret to the Dark One’s vault to hide the blade in the protected force field. But when Mary Margaret gets there she’s shocked to find that the place they are in is from a vision she previously had of Emma crushing her heart. With no time to waste, Lancelot asks Mary Margaret if he could have the honors of placing the dagger in the force field. But his old friend hesitates. That gives just enough time for King Arthur to swoop in and threaten them both.

King Arthur had sent David in the opposite direction and followed Mary Margaret and Lancelot to the vault. He threatens to kill Lancelot unless Mary Margaret hands over the dagger, so Mary Margaret agrees. King Arthur’s dark side is quickly exposed. He revels in the fact that he now has control over Emma and can use the blade to end the darkness and become the greatest king. He commands Emma to appear before him, but Emma doesn’t show. Mary Margaret breaks the bad news to him -- they set him up.

David arrives and it’s revealed that he and Mary Margaret hatched a plan to test King Arthur and Lancelot. Lancelot passed while King Arthur failed and showed his true evil intentions -- he wanted to use Excalibur for evil.

They tie King Arthur up at Granny’s, and Lancelot tells his friends he wants to put someone worthy in charge of Camelot: Guinevere. But the king has his knights waiting for him outside. Guinevere enters Granny’s and releases her husband. After she pledges allegiance to King Arthur, Lancelot puts two and two together and figures out that Guinevere must be under the spell of the sands of Avalon. He begs her to allow him to break the spell, but Guinevere is not interested. She makes the knights remove Lancelot and take him to the castle’s dungeon.

OUAT Season 5, episode 4 King Arthur (Liam Garrigan) has his wife Guinevere (Joana Metrass) wrapped around his finger in Season 5, episode 4 of "Once Upon a Time" thanks to magic sand. Photo: ABC

Mary Margaret and David think they’ll be thrown in the dungeon alongside Lancelot, but King Arthur and Guinevere have other plans for them. They say that they need their help and plan on getting it by using the sands of Avalon to “fix them.” The sand works, and David and Mary Margaret return to the castle to get the dagger from Regina. Meanwhile in the dungeons, Lancelot makes a new friend -- Merida (Amy Manson).

Present Day Storybrooke 

Episode 4 of “Once Upon a Time” ends in present day Storybrooke. Emma is holding a flower similar to the one from the Camelot meadow with Hook. But it’s not a sweet moment -- Emma has Rumplestiltskin tied up in her basement.

“I can’t be the hero you want,” he tries to tell her.

However, Emma has something up her sleeves to “sharpen” him up. Merida is tied to Emma’s yellow Beetle. She thinks Emma is going to kill her, but the Dark One has something else planned. Emma rips out Merida’s heart and tells her she needs Merida to make Rumplestiltskin just like her, “brave.”