"The Song in Your Heart" is the twentieth episode of the sixth season of the American fantasy drama series Once Upon a Time. It first aired on May 7, 2017. Billed as a musical episode, it marks a departure from the typical dramatic elements featured in the series. In this episode, Emma and Hook prepare for their wedding, but Fiona is preparing a plot that will begin the Final Battle. In flashbacks, Snow and David make a wish that results in the entire Enchanted Forest and Oz breaking out in song.
Plot
Opening sequence
An orchestra is shown in the Forest, playing the theme song of the series.
Event chronology
The Storybrooke events take place after the current events of "The Black Fairy", and in 1991 after "Tougher Than the Rest"; the flashback events in the Enchanted Forest occur after the pilot episode and before "The Stranger"; and the events in Oz occur after "Chosen".
In the characters' pasts
Land Without Magic, 1991
At a group children's home in Minnesota, Emma records herself singing, only to have another girl interrupt her, reminding Emma that she will always be an orphan.
The Enchanted Forest and Oz, before the first Curse
After talking with Rumplestiltskin in the castle dungeon, Snow makes a wish that her future daughter will be happy and safe before the Curse takes place. The next day, her wish comes true: Snow and David break into song and realize that they can defeat Regina through the power of music ("Powerful Magic"). The wish also affects Regina, who notices that the entire forest is singing ("The Queen Sings") and makes a plan to destroy everyone's happiness ("Love Doesn't Stand a Chance").
Meanwhile, David and Snow visit a tavern to enlist Hook to help them search for Regina. Hook refuses their offer of gold and explains that revenge on Rumplestiltskin is all that he desires ("Revenge Is Gonna Be Mine"). David and Snow offer to surrender Rumplestiltskin to Hook in exchange for passage on his ship to Regina's castle. Regina visits Rumplestiltskin, who is not affected by the wish, at his cell. Regina asks for his help in erasing the wish, but he refuses. In Oz, Zelena spies on their conversation and believes that Rumplestiltskin might come to regret choosing Regina over her. She prepares a spell for Regina to end the Singing Spell, which she will take credit for ("Wicked Always Wins").
Snow and David confront Regina, and the Singing Spell seems to make Regina's magic ineffective against the Charmings ("Charmings vs. Evil Queen"), but Regina uses a magic box she had found (which contains Zelena's spell) to stop them from singing and sends them back to their castle. Upon their return, the Blue Fairy appears to Snow and David and informs them that the power of song was never meant to be used to defeat the Evil Queen, instead placing it in Emma's heart, where the Power of Song will help her win a major battle one day. The Blue Fairy tells them that Emma won't be alone.
In Storybrooke
As the wedding approaches, Emma is unable to decide on a dress, so Snow brings over the dress she wore at her wedding, which she found at the Pawn Shop. But just moments before Emma tries on the gown, it immediately turns black; they are surprised to see Fiona appear, having thought that Gold had killed her. Fiona demands that Emma turn over her heart, then taunts Emma about believing herself to be orphan, saying that she is still "weak" and hasn't really "grown up," adding that "[she's] still just the lonely little girl [she] always [was]." Fiona lets the women know that she plans to use an enormous amount of Black Fairy Dust to unleash another Dark Curse on Storybrooke at 6:00 PM, the same time as Emma and Hook's wedding. When they check the clock tower at Fiona's suggestion, they discover that Fiona had brought enough Black Fairy Dust to curse Storybrooke more than ten times over.
This prompts Regina and Zelena to come up with a plan to stop Fiona from crashing the wedding, while Emma informs Hook of her decision to face the Black Fairy before the wedding, and says goodbye in case she dies. Hook confronts Gold at the Pawn Shop for lying to everyone about Fiona. When Gold refuses to apologize, saying that he did it for the good of his family, Hook uses Dreamshade on Gold to knock him out, hoping to buy time for Emma to defeat Fiona. Fiona appears, prompting Hook to flee. At the Sheriff's station, Emma gets a sign of encouragement from Henry, but when Henry finds the recording of her singing, Emma says that it's nothing.