Emma has fully embraced the dark while Regina continues to acclimatize to being the new savior in the upcoming "Once Upon A Time" season 5 episode, titled "Siege Perilous." In this installment, the heroes' determination to bring Emma back to her true self is put to the test.

In a clip for this week's installment, there is the question of how far passion can go at least when it comes to striking out darkness from Emma. Sadly, as ominously teased in the promo, "the answer lies in the heart of an impossible quest."

In this "Once Upon A Time" season 5 episode, Hook will continue to get his great love out of the darkness. Emma reveals that this mission entails trust, which she expects Hook to give to her. The clip shows her telling Hook that she will let him go if he says he no longer loves her.

As sincere as Emma may sound, media outlets don't buy this and look at it as a ploy to get Hook to join her in the dark. While Hook is known to put his mission first and not be fazed by anything, there's a reason to worry on this one as the love of his life is the one who's basically asking him to stop trying.

The clip for the intense "Once Upon A Time" season 5 episode also shows Snow and Charming debate on what to do about their daughter, which is not a common sight. Showrunner Edward Kitsis explained to Variety why such is now taking place.

"'Cause Emma came to Storybrooke a nonbeliever and now she is a leader and she's united everyone. So as you saw there, when you take the leader out, everyone starts bickering," Kitsis said.

The couple's squabble scene instantly cuts to Charming and Hook, who will apparently be in grave danger as they go about a certain undertaking possibly to save Emma.

"Once Upon A Time" season 5 episode 3 airs Oct. 11 at 8 p.m. on ABC.