The next day came. Umbra shook herself out, inspecting her mane and patting down the fur of her pelt. She was ready to hit the town. "Shifting!" She emerged from the bedroom, looking around. "Prism?" Oh, there she was, Umbra accelerated to her side in the living room. "There you are. Where are we headed first today?"
"Nowhere..." The tone sent a chill down Umbra's back. "Together."
Umbra came to a complete halt. "What's wrong?"
"You're being rational, and reasonable, and that doesn't make... my feelings just go away. The more I think about it, the more it hurts, and you left me no room." She crossed her arms firmly. "And it's not normal! Monogamy is, what... the default? You shoulda asked before you went and did something else. Besides... Besides... I was caring for your child, and don't even start. She's yours. I was working on changing that, but it isn't changed."
Umbra raised a hoof and opened her mouth, but her argument wasn't coming out very well. She didn't want to argue with Shifting. "I was wrong..."
"I'm glad you see that." Shifting stood up slowly. "But I'm still hurt. And it won't be the last time. You are very reasonable... when you get your way. You're not... a mean person, but a little self-centered." She smiled lopsidedly. "That confidence is part of why I was attracted... I was dumb! I was dumb..."
Umbra's eyes flared with her power, though she was doing nothing with it. "Are you saying--"
"--We're done." Shifting turned away. "I'm...not angry, just... done. You broke a rule that shouldn't ever be broken. I hope, if you find another special... If you do, you'll learn from this."
The dark energy flared brighter, sizzling darkly at the tears that fell. "No," she barely whispered. She had no right to complain. She had no right to stand in Shifting's way. "Please... I'll..." She stopped. She had been about to say she'll get better. But she could remember way too many friends who had been hurt way too many times by people who said exactly the same thing, their abusers sweet talking them into docility.
Maybe she could do that to Shifting.
But then she'd be just as bad... "Can we be friends, at least?" Umbra forced a smile. "O&O won't be the same without you."
Shifting wheeled on her and swatted at her front. "Dummy... I thought you wouldn't want... that. Having your ex partner around... Do you want that?" She scowled. "And it better not be an excuse to try to win me back."
"No no..." Umbra raised her hooves. "This is... my mistake... I... just want to limit the damage. You're fun to be around, even if we're not +1s. I would be very happy to have you as my jeweling buddy and an O&O player."
Shifting leveled a hoof at Umbra. "We can never be... I need to have complete trust, and you broke that, and it wasn't a small thing. Faith... It's delicate... And you smashed it." She hugged herself, hooves pressing into her sides in the squeeze. "It hurts, and you can't fix it..."
Umbra's ears fell back. Momentary thoughts of dark magic rose. She could fix it. She could fix it all with the right terrible bits of magic. But then she would be outright admitting she was a monster. A terrible thing worthy of scorn. "I'm so sorry..."
"Me too," barely got out Shifting. "Me... too..." She turned for the door. "Have a safe trip, Umbra. See you at the next session." She fled before she could second guess herself. She was doing the right thing, Umbra decided, standing up for herself and setting the firmest of boundaries. Would that her old friends had that strength.
It made Umbra all the sadder that this wonderful lady was leaving her, and she deserved it. Umbra slammed a hoof down with a grunt, alone in the living room. "Damn it..."
"Mother." There was Morning, peeking out from a hallway. "Are today's plans..."
"Aborted," grunted Umbra, offering a hoof. Thankfully, it soon had a Morning in reach of it. She drew her little monster of a filly in close, hugging them. "Your mother did something very stupid... and got what she deserves."
"What did you do, Mother? Did you lose a battle?" She curled in with Umbra, a warm little nightmare. "I can fight if you like?"
"I did lose a battle, though foolishness. It is entirely... I did this to myself." She curled in, touching nose to nose with Morning, gazing into her eyes. "If you find a creature worthy of your heart, do not lie to them. Do not skirt the rules with them. If they are that wonderful... they don't deserve that, and you deserve a special someone you never have to hide secrets from."
"That is a lot of faith, Mother." She sat up, still a moment. "I'm not sure I could trust that much."
"You trust me, don't you?" Umbra sat up properly, letting Morning sit on her own.
"Yes, mother. If you wished for my destruction, you would have it." She glanced towards the door. "Why don't you destroy her? She is clearly not going to give you what you want."
Umbra winced at the idea. "Because only a weak person hurts because they didn't get what they want. My plans will adjust, without her as my special someone, but I made the mistake. I deserve to be hurt way more than she does."
"Hm." Morning didn't sound convinced. "Just tell me when, mother. I can make her regret her decisions."
"You will do no such thing." Umbra wriggled her nose. "It was my mistake..." She considered where to go and what to do. She had little further... "Oh, we should visit Celestia."
"The sun princess?" Morning rose to her hooves. "She is not... like us."
"She's about the opposite, but she's also the loving sister of Luna. We can get along." She gently nipped her daughter's ear. "Yes, let's talk with Celestia."
They left together. The guard at the castle nodded at them. "Umbra Shadowheart." He did not bar the way. "I was not informed of your visit."
"Celestia left an open invitation." Umbra advanced past the guard, the way open. As she advanced into the castle, she could think of the family name. Shadowheart. Her heart felt that way... She hadn't selected the name for that, a bit of poor irony? Was that using irony correctly? She shook her head as she went through the richly appointed halls. "Equestria architecture is not Crystal Empire."
"Far less crystals," agreed Morning gently. "More stone. Solid. More painted windows, flimsy. A contradiction. Are they trying to be more or less fortified?"
"I think Celestia loves having her cake and eating it, if she can get away with it." Umbra sped up with a little smile. A chat with Celestia sounded like maybe fun, even if they would likely talk about some unfun things.
They found Celestia where she spent much time, in her courtroom. She sat on her tall throne, speaking to various supplicants that advanced in front of her. "We have heard your plea," she assured one pony. "Your permit will be granted, assuming approval of the city mayor." She raised a hoof, a stamp could be heard thumping down. "Take this to their office for final approval."
The pony walked off with a big happy smile, clearly getting what they wanted.
Celestia saw Umbra, hard to miss that large shadow mare. "Guard, see Umbra to the late spring room. I'll be there after we adjourn." And swiftly did she banish Umbra to continue her affairs.
Umbra didn't fight that, following the guard along. "She looked quite busy."
"She usually is, ma'am," crisply replied the guard. "Here we are." He willed the door open, a unicorn. "If you require anything, please let a maid know."
Umbra made sure Morning was with her and headed inside. "I heard rumors..." And they weren't wrong. Sweet treats were already arranged, including little cakes and cookies. Celestia had a sweet tooth. "In the mood to teach sweet things a lesson?"
"Gladly." Morning hopped up into a seat and held out a hoof patiently for Umbra to float a cookie into it. She reduced it to a sad crumb pile that was full of nothing but regret. "Well made, mother."
"I would hope so." Umbra sat next to her, floating a cookie to join her daughter, though she ate less voraciously. "Mmm..." It didn't distract her from what had happened that day. How she could have acted better played in her mind, starting with the most obvious point. She could have just not played with Starlight... Why did she think that was alright?! It wasn't alright... It was so not alright...
"Mother?"
Umbra quirked an ear and a wing. "Hm? Sorry, thoughts wandered off."
"You should keep better control of them," gently counseled Morning. "Umbrum do not tolerate wandering thoughts. We control them."
Umbra gently rubbed the top of Morning's head. "You do an excellent job of that. I'm not sure if I mentioned this, but I wasn't always an umbrum. That may be why it doesn't click... But then I wasn't a wizard either, and that's working fine." She shrugged at that. "We all have our talents. I look forward to seeing how your mastery awes us all. You won't let anything hurt our ponies, right?"
"Correct." Morning nodded in easy agreement. "I will not let them damage our property. I can't scare them if something else does it, mother." She perked an ear. "Something large is coming."
The door opened an instant after that, allowing Celestia to step into the room. "Good afternoon." She nodded to each of them with a soft smile. "You should have warned me, or I wouldn't have made you wait."
Umbra raised a hoof swiftly. "My fault." She had a lot of those recently... "But you said to visit you, about the mirrors?"
"Ah, yes..." Celestia sank at the table, sitting. "There are countless mirrors, and they defy easy explanation... Even counting them has proven impossible. Whenever we think we have arrived at a number, we find a new mirror, or one goes missing. Portals to other possibilities, there may be no definite answer to how many of those there could be."
Umbra perked at that, interest growing. "That makes sense. You made countless new worlds just walking into here."
"Did I?" Celestia glanced back at the door she entered through. "I wasn't trying to."
"But you did anyway." Umbra pointed at that same door. "Let's start with that door. You could have come in a different way." She pointed to the door she had come in through. "You could have walked through the door. You could have ripped the door off its hinges and tossed it aside. Left? Right? More worlds. More possibilities. Maybe you got 3 brushes this morning, maybe 2, or none, the horror. Maybe you have a maid with you, still brushing even as you walk in. Infinite possibilities."
Celestia's eyes shone with wonder at this concept. "I feel like a foal, even trying to count them then... Why are you so educated on this matter? I'm not complaining... but quite curious." She sank her teeth into a slice of cake. "Mm, Vanilla, but, I suppose, it could have been carrot, or strawberry, or... Infinite indeed. What if I had started with a cookie, or some tea?"
Umbra clapped with a smile. "You got it! There's a reason you're a princess, clever thing." It was always nice when the ponies were quick on the uptake.
Celestia smiled gently. "I do appreciate the compliment, but my question remains."
"Ah, right. In my world... My original world... There was a lot of thought about this. I didn't make it up, just learned it from others that had thought about it long and hard and passed it along. And now I've passed it to you. I think they'd be happy to know their knowledge has passed on so far."
"So you have mirrors too?" pressed Celestia with curiosity shown.
"Oh, no! No no... Only in theory, but we can spend a lot of time thinking about theories, so..." Umbra took some of that mentioned tea. "Idle brains can make for interesting thoughts."