Ursula makes an appearance in the forest.
In The Characters' Past
In the Neverland realm, Hook and his crew hear a mermaid’s song, which distracts them until they almost strike a series of rocks. Around the same time, the father of the Seas, Poseidon, scolds his daughter, revealed to be Ursula in her youth, for ending the song just in time for the Jolly Roger to escape. Later on at a tavern during a port stop, Hook recognizes the same tune being sung by Ursula, and offers her a drink. She explains to Hook that her father kicked her out of his kingdom for disobeying him, so she stole a magical bracelet that allowed her to walk on land. Ursula also reveals that her mother was killed by a pirate, which is why Poseidon demands Ursula use her voice - the only thing that reminds her of her mother - to steer the ships awry. Hook tells Ursula that listening to her voice was the only thing that has ever taken away his lifelong pain. She shares her plan to sing in Glowerhaven, and he offers to take her there on his ship. Poseidon learns of this and instructs Hook to remove Ursula's ability to sing by using a seashell, in order to ensure that she will never leave the ocean, in exchange for giving Hook a vial of squid ink, which Hook can use to paralyze his enemy Rumplestiltskin.
Later, Hook returns and tells Ursula about her father’s plan. Although he refuses to break his personal code, Hook does asks Ursula to steal the squid ink from her father’s storage. Ursula agrees, only to have Poseidon catch her, and in return for Hook betraying him, takes away his only chance to seek revenge on Rumplestiltskin. Hook then counters by stealing Ursula’s singing voice to hurt Poseidon. After Hook leaves with Ursula's singing voice, the rift between father and daughter continues, prompting an enraged Ursula to snap and use Poseidon’s trident to transform herself into a powerful sea goddess stronger and more powerful than her father.
At Gold's remote cabin, Regina, Maleficent, Cruella, and Ursula start interrogating adult August Booth about the Author. He explains that he stole the research of a man in Hong Kong named The Dragon, and that the research is still currently in Storybrooke. Gold heads to August's trailer to get the research, and Regina uses her magic to briefly take over Mary Margaret’s body to tell Emma, Hook, and David that August is safe, Gold is back, and the Queens have something big planned. They later relay this to Belle, who tells them that she gave the Dagger to Hook, only to learn that Gold transformed himself into Hook to retrieve it, leading them to discover that Gold has restored his powers once again with the dagger. This information gives Hook an idea as he reveals his past encounter with Ursula, saying that the time has now come to take advantage of the Sea Goddess and to restore her happy ending.
Later, Hook uses a conch shell to summon Ursula and he offers her a deal: in exchange for finding out Gold's plan involving the Author, Hook will return her voice. When Ursula asks Hook where the magical shell, he responds that it is located inside the Jolly Roger back in the Enchanted Forest. Ursula opens a portal into the Jolly Roger, which has been turned into a model ship in a bottle. Hook and Ursula, with help from Will Scarlet, restore the Jolly Roger. Hook gathers the shell with Ursula’s voice and returns it to her, but the magic does not work and her voice does not return. A furious Ursula then takes her revenge out on Hook by saying that the deal is over, and uses her tentacles to send Hook overboard. He is rescued by Ariel, who explains shot that Blackbeard used the Jolly Roger to terrorize people, including Anna and Kristoff from Arendelle, so Queen Elsa contained the ship in a bottle, accidentally trapping Ariel as well, and thanks to Hook, Ariel is now free and repays him with a favor.
Regina is still trying to control her feelings for Robin Hood, and has a nightmare in which she fights the "Evil Queen" version of herself over the affections of her former love. Gold suddenly returns from August's trailer to inform her that August lied about The Dragon. He feeds August a temporary, painful potion that turns August back into wood and causes his nose to grow every time he lies, and holds August's nose to the fire. August says that the Sorcerer trapped the Author behind a door but he does not know where the door is, except that it is in Storybrooke and that Regina has seen it before in one of the pages. Gold, Regina, and Maleficent head to the Sorcerer's mansion to look for the door. Moments later, Emma, Mary Margaret, and David break into Gold’s cabin and knock out Cruella. They are then surprised by Ursula, who briefly uses her tentacles to strangle Mary Margaret before being surprised by Hook, who tells Ursula that only the person who enchanted the shell can reverse it. Poseidon appears, having been brought through a portal by Ariel. Poseidon apologizes to his daughter for everything, and returns her singing voice so that he can hear the voice of his wife one last time. After Ursula and Poseidon are reunited and leave, Hook tells Emma that his happy ending is to be with her, but he fears he will lose her because he is a villain. August is rescued but Cruella has escaped, and later meets up with Gold, Regina, and Maleficent, saying that Ursula was a mole, much to Regina’s relief.
Hook learns from Ursula about Gold's plans, revealing that as long as Emma is in Storybrooke to give everyone their happy endings, the Author will be unable to give villains their happy endings while there is still a savior present, and the only way to change that is for Gold to fill Emma’s heart with darkness. At the same time, Regina meets with Emma to ask her if she can help track down Robin Hood and later asks August about the door; August says that the picture of the door is not just an illustration, but is the door itself. The Author is actually trapped inside the "Once Upon a Time" book.
- Ginnifer Goodwin as Mary Margaret Blanchard
- Jennifer Morrison as Emma Swan
- Lana Parrilla as The Evil Queen / Regina Mills
- Josh Dallas as David Nolan
- Emilie de Ravin as Belle French
- Colin O'Donoghue as Hook
- Jared S. Gilmore as Henry Mills
- Michael Socha as Will Scarlet
- Robert Carlyle as Mr. Gold
- Eion Bailey as August Booth
- Kristin Bauer van Straten as Maleficent
- Tiffany Boone as young Ursula
- Merrin Dungey as Ursula
- Christopher Gauthier as William Smee
- Ernie Hudson as Poseidon
- Sean Maguire as Robin Hood
- Victoria Smurfit as Cruella De Vil
- Joanna García as Ariel
- The episode is named after a song from the The Little Mermaid.
- Ursula vocalizes the reprise of "Part of Your World" and sings "Fathoms Below" from The Little Mermaid during the episode.