The first volume's plot revolved around the main characters traveling to Neverland from Storybrooke to retrieve a kidnapped Henry Mills from the possession of an evil Peter Pan.

The second volume's plot followed the characters' past journey in the Enchanted Forest and how they were brought back to Storybrooke by Zelena, the Wicked Witch of the West and Regina's half-sister, while also documenting Emma's mission to break the new curse and save her family.

Emma and Henry are brought back to Storybrooke to help break the latest curse and defeat the Wicked Witch, which leads to a trip to the past with dire consequences.

Everyone in Storybrooke joins Mary Margaret and David as they prepare to crown their newborn son, while the time-travel portal that Zelena created before her apparent demise comes to life, and takes Emma and Hook back to the Enchanted Forest, before the events of the original curse.

But in their quest to return, they accidentally ruin Snow and Charming's first meeting, and they must repair the timeline with Rumplestiltskin's help, before it is too late to undo the damage.

[23] On August 4, 2013, it was announced that the season would be split into two parts, with the first eleven episodes premiering from September 29 to December 2013, while the second half would broadcast from March 9 to May 2014.

[25] On March 10, 2014, the producers revealed that they may look ahead at incorporating characters from the films The Princess and the Frog, Brave, and Frozen in future episodes, possibly towards the end of the third season if they get the green light from Disney.

[30] In May 2013, it was revealed that season two regular Meghan Ory would be departing the show to star in CBS's upcoming sci-fi drama Intelligence.

[27] For episode five, Bernard Curry played a guest role as Captain Hook's brother Liam,[36] while a member of the Lost Boys called Devin was portrayed by Skyler Gisondo.

[47] In February 2014, a casting call was opened for an actress in her mid-to-late twenties to recur as Glinda the Good Witch, a role later landed with Sunny Mabrey.

[48] After Once Upon a Time in Wonderland was canceled, it was reported that Michael Socha, who plays the Knave of Hearts in that series, was in talks to join the main cast in season four.

The expensive set took a month to construct and was inspired by both Disney's animated Peter Pan movie and the Ewok village from Return of the Jedi.

We have 200 real plants that have to be watered and pruned every day and heated at night, 30 actual tree stumps and 450 fake branches" to which silk leaves were added.