In the next episode of “Once Upon a Time,” ABC’s contemporary revamp of classic fairy tales, Emma Swann (Jennifer Morrison), the daughter of Snow White and Prince Charming, continues her season-long transition into the evil “Dark Emma.”

A teaser for the upcoming episode, titled "The Broken Kingdom,” shows the hallucinatory stress that is tormenting her during this transition. In a promo clip for the episode, the always sinister Rumplestiltskin (Robert Carlyle) tries to goad her into reaching out for an enchanted dagger.

“Do you hear it?" he croons. "A sweet sound, a strage sound. Let’s go have a look, shall we?”

As Emma reaches for the dagger, she realizes that there is some tough magic keeping her away and comes to her senses.

"Your friends cannot protect you,” Rumplestiltskin teases, before Emma shoots some magic his way and nearly zaps her boyfriend Hook (Colin O'Donoghue), who tells her to calm down, before embracing her.

In Episode 4 of Season 5, Dark Emma will stick to her plans to draw Excalibur from the stone and unleash a secret weapon.

In a video interview with The Wall Street Journal, the 36-year-old actress, whose previous TV credits include roles on “House” and “How I Met Your Mother,” sounds as if she is totally enjoying her character’s descent into the dark side.

“I have to say I am really enjoying playing a villain,” Morrison said. She went on to discuss Emma’s turn toward villainy.

The actress said, “[Emma] is constantly dealing with the darkest parts of herself being exaggerated.” This season, viewers can expect revenge and a lot of long overdue anger from her. According to Morrison, Emma “is not putting others first anymore.”

The next episode of “Once Upon a Time” airs Sunday, Oct. 18 on ABC.