In the Everfree forest, in the old castle of the Two Sisters. The underground chamber that was once was the workshop of Starswirl was once again being used. Celestia has been working in the workshop, reading the old notes and using what she had learned from her mentor to create her own mirror portal. Since Sunset left, she's been working none stop to create a way to go to other worlds to search for her.

"Sister you need to rest," Luna said who is now the only remaining ruler of Equestia.

"No, I can't stop," Celestia said as she experimented in creating another portal mirror.

"Sister I know you want to find Sunset but you can't let it destroy you," Luna said.

"There is nothing but you here for me," Celestia said.

"But what about your friends?" Luna ask.

"What friends? All I have are subjects. Sunset made me see that for all my talk about friendship, I have no real friends," Celestia said.

"You can make friends," Luna said.

"After I make things right with Sunset," Celestia said.

"You do know that even if you do create a portal. It could take you years just to find her," Luna pointed out.

"I know that, but I have to find her and earn her forgiveness," Celestia said.

"Is she really that important to you?" Luna ask.

"How could you ask such a thing?" Celestia ask.

"You never cared before," Luna said.

"I have been suppressing it long enough. I could had been the mother she needed and yet I couldn't be one to her. I kept putting it off after she went into the mirror. Thinking that I have all the time to do it," Celestia said sadly.

"But now she isn't the filly you knew anymore and isn't looking for a mother anymore," Luna said.

"I have to make it up to her while I still have a chance to do it. I will not put it off anymore now that I have nothing else but you to keep me here," Celestia said.

"Stepping down from the throne and leaving me to rule while you go off to look for your wayward daughter? Many of the ponies want you to stay," Luna said.

"I have someone more important to find. For all I have done as princess of Equestia. It has left me with just about nothing in my personal life. Sunset is the only daughter I had, and I didn't see her as mine till it was too late. I will make it right between us no matter the cost," Celestia said.

"But if you go through with this you be going to one world after another with nothing," Luna said.

"And that was what I put Sunset through when I didn't try to get her back for years. I could had written to her, but I didn't. She was just a filly having to live in an alien world all on her own. I won't let anything stop me from being the mother she wanted and needs," Celestia said. (1)

"And does she need you anymore?" Luna ask.

Celestia didn't say anything for a very long time.

"I can only hope at this point," Celestia said finally.

"I read stories about parents who stayed or been apart of their children's lives for most of their life. And suddenly wants to be in their kid's lives again. When their child has already lived most of their life without parents or knowing anything about each other. The parents have missed out in so much of their child's life that all the things that a parent should know about their child, they just don't know," Luna said.

"I know that. I have to do this. I have to have my daughter back," Celestia said.

1 - I really wished that they would expand on the Celestia and Sunset thing then just pushing it to the sidelines.