In the special, Elena travels to Nueva Vista, a place that she used to visit when she was a child, and reconnects with her cousin Duke Cristóbal, who has been keeping watch over the city. While there, she encounters a group of mermaid-like sea creatures called sirenas and learns about their complicated history with humans. In an attempt to make amends, Elena befriends the sirenas and enlists their help to defeat evil sorceress Shuriki. Gina Rodriguez and Prince Royce guest star as twin sirenas, Princess Marisa and Prince Marzel. Edward James Olmos and Rita Moreno voice their parents, King Pescoro and Queen Camila. Rosario Dawson voices the role of sirena royal guard, Daria. Jane Fonda recurs as Shuriki. Javier Muñoz also guest stars as Elena’s cousin, Duke Cristóbal.