In Fairytale Land past, Snow White is cornered while trying to outrun the queen's soldiers. She jumps off a cliff plunging into the waters below. Snow sinks toward the bottom of the sea until a mysterious figure pulls her to safety. She's just been rescued by a legendary creature with a fin instead of legs. It's a mermaid. Her name: Ariel (guest star JoAnna Garcia Swisher). She loves a prince named Eric. She once rescued him, too. It was love at first sight. Ariel hopes to meet him at the annual Under the Sea celebration. All she needs are legs. Fortunately, the sea goddess Ursula gives mermaids this gift for a short time. Ariel has 12 hours to find her prince.
Snow White accompanies Ariel to the Under the Sea celebration. She helps her understand that a fork is not a mini-trident. Ariel shares a dance with Eric, who recognizes her face from a dream he had after his shipwreck. He says Ursula saved him and showed him a vision of his future. He believes it's Ariel. He invites her to join her on a journey around the world. All she has to do is show up the next morning. The Evil Queen witnesses these events from afar.
Ursula appears from the depths of the sea to help Ariel with her dilemma. She looks a lot like the Evil Queen though. Ariel is offered a chance to be with her prince. She attaches a magic bracelet to Snow White which turns her into a mermaid. It's the price that must be paid to keep her legs. Ariel thought this was good news for Snow White so she could escape the Evil Queen, who was behind this trick the entire time. Regina strangles Snow until Ariel stabs her with a fork she swiped. The bracelet is removed. Ariel takes Snow under the sea as they escape from the Evil Queen.
Once Snow White is safe, Ariel swims off to find her prince. She's going to tell Eric the truth. Ariel swims up to his ship. She tries to yell to him, but nothing comes out. Ariel's voice is gone. Regina is behind this. She stole her voice so Ariel would never know if her prince would want to be with her. Eric is gone and the little mermaid must swim back into the sea alone. As for Regina, she's contacted by the real Ursula, who threatens her with one of her tentacles. This is a warning. The Evil Queen is to never pose as Ursula again.
In the present, Regina tries to teach Emma how to use magic. David thinks this is a bad idea, but Mary Margaret believes their daughter needs to know how to use her gift. Hook lets the two of them know that Neal is alive. They agree to keep this info from Emma until they confirm this is true. That's the plan for about five minutes right up until the moment Mary Margaret blurts out the news to her daughter. Regina doesn't buy any of this, so she heads off to find Henry on her own. As for Neal, Pan has him moved to the Echo Cave. He says the game is about to get interesting.
Peter Pan makes Rumplestiltskin his favorite breakfast, eggs in a basket. He lets him know that he is free to leave the island, but Rumple isn't willing to abandon his son and grandson. Belle wants him to start a new family with her in Storybrooke. Regina shows him that the vision he's been speaking with is nothing more than one of Pan's tricks. She needs him to join forces with her. Rumple knows of a spell in his shop that may take care of Pan. All they need to do is get back to Storybrooke.
Emma and the others reach Echo Cave. Hook says he lost half his crew to this place. The only way to rescue someone from inside is to reveal a secret-the darkest secret. Pan believes this will be their undoing. Emma sees Neal in a hanging cage. The only way to get to him is to start spilling secrets. Hook kicks things off by saying that he kissed Emma. Mary Margaret reveals she feels cheated out of Emma's childhood, so she wants another baby. David lets her know that he can never leave Neverland after taking the cure for Dream Shade. These truths help create a rock bridge which allows Emma to cross to Neal. She can't free him until she, too, reveals a secret.
Emma lets Neal know that she felt terrified when she learned he might be alive. She never stopped loving him. She probably always will. But she was secretly hoping he was dead so she wouldn't have to face the pain she went through before. With this final truth, Neal is freed. The group heads off to find Henry. While doing so, Neal reveals his secret that he's never going to stop fighting for Emma. Hook overhears their conversation. Elsewhere, Regina summons Ariel from the sea. Mermaids can travel through realms, so she can get to Rumple's spell. She'll need legs for her journey to Storybrooke where Regina says Prince Eric resides.