Once Upon A Time Season 4 Episode 15 "Poor Unfortunate Soul"
Ursula: Gold's plan... I'm afraid it involves Emma. She's the only way he can secure happy endings for the villains.
Hook: Well, I thought he was gonna get the Author to rewrite everyone's stories.
Ursula: It's not that simple. The Author can't just change things in this world because he didn't give everyone their happy endings here. Emma did. She's the savior. And as long as there's a savior, The Author can't give the villains what they really want. And the Dark One knows this.
Hook: The Dark One's gonna try to kill Emma?
Ursula: Worse... he plans to fill her heart with darkness forever.
