Somewhere travelling across the sea aboard a boat known as The Floating Palace, Sofia is in the library reading a story when the royal family arrives at a tropical island known as Merroway Cove for a vacation. Also accompanying the Royal family is Cedric who is out on another scheme to take over the kingdom only this time he's not after the Amulet of Avalor.
On the swimming deck Sofia spots a young mermaid who gets herself tangled in a fishing net. Sofia helps the young mermaid also known as Oona get untangled only to have a hurt fin. Then to their amazement, Sofia's amulet grants her the power to turn into a mermaid. Happy with her new powers, Sofia decides to head down below and help Oona return home.
Oona takes Sofia to a shipwreck, that she calls her hideaway and they meet her friend Sven, a seahorse and her older sister, Cora. Cora wraps Oona's sore fin with seaweed and later they go to Oona's castle where they meet her mother, Queen Emmaline. It turns out the Merpeople of Merroway Cove are not pleased with the arrival of the Floating Palace and show they have a dislike for humans, saying they're dangerous.
Sofia admits she's a human too and promises to convince her family to move their Floating Palace. However her family and most especially Admiral Hornpipe don't believe that mermaids exist.
Things get worse when Cedric who has transformed himself into a sea monster, captures Oona for her magic hair comb. Sofia returns to warn Queen Emmaline of her young daughter's kidnapping but Plank informs Sofia there are no sea monsters in Merroway Cove. Instead he believes that Sofia's family has kidnapped Oona. Queen Emmaline warns Sofia if she does not return her daughter before sundown, she will sink the ship with her family on it by creating a massive storm.
Sofia goes back to the Floating Palace to warn them but to no avail because they refuse to believe that merfolk and sea monsters are real. Sofia, finally sick of trying to tell others the truth only to be called a liar by everyone around her but Sven because of what Roland, Amber and Admiral Hornpipe said, decides it's now up to her and her animal friends Clover, Farley and Sven to find the Sea Monster Cedric and rescue Oona but they fail.
Sofia feels terrible because she failed to save Oona and her family will be drowned for a crime they never committed. As all hope seems lost, Sofia's amulet summons Princess Ariel. Through a song, Ariel convinces Sofia not to give up and this is when she decides to go find Cora for help. At first Cora refuses to believe what she says until Sven steps forward.
Meanwhile Emmaline uses her trident to create a giant storm to sink the Floating Palace but Sven stops her before it gets too fierce and take her and a stubbon and deluded Plank to where Oona is held captive. While this goes on, Sofia and her friends find where Sea Monster Cedric is holding Oona and with help from Cora she gains possession of Oona's comb and uses it to get rid of Cedric. Oona reunites with her family and Emmaline puts an end to the storm with deep apologies to Sofia.
As the sun sets, Sofia's family finally gets to meet the Merpeople and Sofia and Oona are able to stay as friends.
Home Video Release
- Ariel Winter as Sofia
- Sara Ramirez as Queen Miranda
- Wayne Brady as Clover
- Tim Gunn as Baileywick
- Darcy Rose Byrnes as Princess Amber
- Zach Callison as Prince James
- Travis Willingham as King Roland II
- Kiernan Shipka as Oona
- Jodi Benson as Ariel and Queen Emmaline
- Jeff Bennett as Farley
- John Ross Bowie as Sven
- Phil Morris as Plank
- Sarah Mitchell as Cora
- Jess Harnell as Cedric the Sorcerer
- Jim Cummings as Wormwood
- This is the second time a Disney Princess shows up in a special (Cinderella) and the second special of the show (Sofia the First: Once Upon a Princess). There are also similarities especially between these two meetings:
- Sofia covers her eyes in despair seconds before her amulet glows and a glow is seen where the summoned princess will appear.
- Both state that the amulet summoned them to help.
- The princesses (Sofia and the summon) take a stroll (or a swim) in both cases.
- The meetings include a musical number, and both hint on what Sofia should do to set things right and the one person (Princess Amber and Cora) she should converse with to get started.
- The strolls end in a doorway to a "room" where an older girl is sulking (Princess Amber and Cora).
- In the last word of the musical number the summoned princess and Sofia are in the same position in both cases, with Sofia facing the doorway and the princess right behind her, hands rested on the former's shoulders and as Sofia turns round to thank her, the princess had magically disappeared leaving behind a cloud of shimmering stars.
- As Sofia meets the girl, they respond negatively at first until Sofia declares her mission to her. Both missions also involve a confrontation with Cedric or at least Wormwood with both girls working together.
- This is the third time Sofia undergoes a magical transformation. In "Cedric's Apprentice", she became a lizard. In "The Amulet and the Anthem", her voice became that of a frog.
- This is the second time Sofia strengthens ties between her family and supernatural creatures. Before, it was the trolls in the episode "Let The Good Times Troll".
- Ariel is the fourth Disney Princess to assist Sofia.
- Ariel is the first princess to not to be seen in her redesign as she was in her mermaid form.
- When Oona asks what kind of animal Clover is, he says "I'm a Blue Ribbon Bunny," a reference to the song and the seventh episode.
- Oona, in many ways, is similar to Sofia. Both are princesses who are the youngest members of their kingdom's Royal family and possess a mystical object given to them by their parents, which gives them magical powers.
- The timeline of the series seems to be falling into a year since Sofia became a princess. Jade stated in "The Little Witch" that Lucinda arrived a few months after Sofia left. "Princess Butterfly" took place on Halloween, "Great Aunt-Venture" in November (most likely) and now a vacation, followed by winter holidays
- This is the second episode where Cedric doesn't go after the Amulet, the first episode was "Tea for Too Many".
- Cedric undergoes a magical transformation for the first time in the series and so does Wormwood.
- This is the second time Cedric not only doesn't go after the amulet, but also doesn't want to take over Enchancia. The first time was in Tea for Too Many. This is also the first time he went after a different kingdom, showing that Cedric wishes to rule a kingdom, but has little preference for which one.
- This is Cedric's last appearance in the first season.
- This is the only episode where James is seen shirtless.
- It's revealed that Sofia may not be a strong swimmer because Miranda states that Sofia isn't supposed to go swimming by herself, until she transformed into a mermaid with nobody looking.