The upcoming 17th episode of "Once Upon a Time", "Heart of Gold," features the return of the Wicked Witch who will undoubtedly wreak havoc in the land of Oz, On the Flix reports.

The Wicked Witch will possess powers that are greater now more than ever and will cause trouble throughout the land.

Meanwhile, Mr. Gold will blackmail Regina and his quest to finding a happy ending will still be in full effect, according to Enstarz.

Emma will also be featured in the new episode as she is still reeling from the news of her parents' history with Maleficent. She faces the challenge of remaining calm despite the news and instead chooses to focus on finding Author, who is lost in Storybrooke.

"The episode will feature a Fairy Tale Land flashback in which Mr. Gold/Rumplestiltskin asks Robin Hood (Sean Maguire) to steal a 'valuable magic elixir' from the Wicked Witch (Rebecca Mader)." 

The Wicked Witch/Zelena's return is being promoted as a big focus in the upcoming episode. Her return comes as a huge surprise since she was killed by Rumplestilskin towards the end of Season 3.

Last week's episode, "Best Laid Plans," included a flashback of Snow and Charming searching for a way to make sure that their son will grow up to be a hero.

In the flashback, viewers watched as a traveling peddler directs Snow and Charming to an old hermit that presented them with an opportunity to ensure that their child will have heroic qualities.

However, the hermit warned them that their child's abilities will come at a price that will haunt them for many years.

So far, the upcoming episode's promo has garnered praise from fans that are excited to see the return of the Wicked Witch.

Although Zelena is completely evil, it's certain she has made fans. In the promo video, some users commented on how they were excited she was back on the show. But ABC showed a different side to her and the rest of the characters by posting bloopers for April Fools. 

"Once Upon a Time" airs Sundays at 8 p.m. ET/PT on ABC.