Another dark curse was being cast by an unknown villain. Everyone would return to the Enchanted Forest except Eva and Henry. They were born in Storybrooke and wouldn't be sent back with the others. Emma could stay because she was the savior. She chose to stay with her son and sister.
Regina had a difficult time being in the Enchanted Forest and away from her daughter and grandson. Everyone missed those who had to be left behind, but Regina was utterly devastated. They all tried to enter the castle, but there was a protection spell on it that Regina couldn't get past. She went to a hidden entrance to a tunnel and was followed. Regina turned and noticed who had followed her, "my God, you're annoying."
"Well, I can't have going and getting yourself killed," Robin Hood said.
"I can do this myself."
"Really?" Robin pointed at the cane.
"Just because I need this right now doesn't mean I'm incapable of taking care of myself."
"No, but it makes you more vulnerable to the person occupying that castle."
"Fine, just don't get in my way."
"I wouldn't dream of it." He noticed that Regina was hesitant to go down the stairs that led to the tunnel, "let me go first. That way if someone is down there, I get hit." He took a couple of steps and held out a hand for Regina. She took his hand and they slowly made their way down the stairs.
"Thank you," she said softly.
"You're welcome," Robin was a bit surprised when Regina took his arm, but he didn't mind. They reached the vault and noticed that the door was open.
"That's impossible," Regina said. "I sealed it with blood magic."
"Look, I know that you said you can take care of yourself, and I'm sure that's true, but maybe I should check out your vault first?"
"I'm fine," Regina said. Inside the vault, Regina grabbed a few things and led Robin to her old suite.
"What are you going to do with those?"
"Make a sleeping curse."
"What?"
"I can't live knowing I will never see my daughter or grandson again. I won't wake up unless it's one of them." Regina used magic to hold Robin in place before taking the cursed needle and heading out the door to the balcony. She removed the protection shield and was about to prick her finger, but a visitor showed up.
"You must be the Wicked Witch."
"I am," the witch said, "you can call me Zelena."
"Right now I'm calling you a trespasser."
"Oh, I'll be leaving soon enough."
"Is that my dress."
"Yes, but it looks better on me."
"What is this all about?"
"You ruined my life and now I'm going to destroy yours," Zelena said.
A realization came over Regina, "it was you. You're the one who altered the dark curse before I cast it."
Zelena smiled, "guilty."
"I've never done anything to you. How could you do this to me?"
"Our mother threw me away and kept you. Everything I ever wanted, you had."
"Our mother?"
"Surprise!"
Regina certainly was surprised. She made a mental note to have that conversation with her mother later. "That was all Cora."
"Well, killing you was going to be my way of paying her back."
"I had a five-year-old daughter I had to leave."
"You took her from her real parents. I did her a favor."
"And they called me 'evil'."
"I'm not evil. I'm wicked and that's much worse."
Zelena hopped on her broom and flew off. Regina went back inside and disposed of her needle. "You didn't do it?"
"No, I didn't." Regina unfroze Robin.
"Why not?"
"That witch ruined my life because Cora ruined hers. I want revenge."
Cora rushed into the room and Robin excused himself, "are you alright? We can't find the witch anywhere."
"She just left. Turns out she just wanted to get me here to try and ruin my life even more."
"I don't understand."
"She's the one who tampered with the curse. She's the reason I became too disabled to care for my daughter, the reason I lost my daughter and nearly died, and the reason I have brain damage."
"Why would she do that?"
"You tell me. I mean, she's your daughter, mother."
Cora was stunned, "Regina, I can explain. I had to give Zelena up. I was engaged to Leopold who dumped me when Eva found out and told him. Your father had been interested in me and this was my best chance."
Regina closed her eyes and put her hand on her forehead, "fine. I need to lie down."
Cora took her daughter's arm and helped her to bed. She used magic to get Regina into more comfortable clothes and tucked her in, "I'm sorry that you paid the price for my actions. I never wanted that."
Regina could tell that her mother was genuinely sorry, but she was too tired to respond. Instead, she fell asleep. Cora decided to stay with her daughter to watch over her.
It was revealed that only the strongest light magic could defeat Zelena. That meant they had to get back to Storybrooke and find Emma. They also discovered that Peter Pan had cast the curse that sent them to the Enchanted Forest and was also Rumple's father. Snow cast the curse by sacrificing David's heart. Regina split Snow's in half and gave half to David after Zelena showed up and altered the curse again. Regina was terrified that she would be sick like the last time.