The Dark Swan

"The Dark Swan" is the 90th episode of Once Upon a Time, as well as its fifth season's premiere.

Summary
Immediately after becoming the Dark One, Emma disappears and the heroes must band together to save her, but first they have to find her, which will require the help of an unlikely ally. Meanwhile, in the Enchanted Forest, Emma struggles to resist her dark urges as she searches for Merlin in the hope that he can stop her transformation. Along the way to Camelot, she gets help from the plucky and brave warrior princess Merida, as well as King Arthur and his Knights of the Round Table.

Trivia

 * As of this episode, Michael Socha (Will Scarlet) is no longer a series regular. In turn, Rebecca Mader (Zelena) and Sean Maguire (Robin Hood) join the main cast.

Production

 * The title of this episode was revealed by Mark Isham, via his Instagram account, on June 30, 2015. . It was then officially confirmed by executive producer/co-creator Adam Horowitz, via his Twitter account, on July 7, 2015.

Gallery
Gallery of photographic stills released to promote the episode.