Cadence paced back and forth. This was a moral dilemma the likes of which she had never seen before. Help Luna and breach upon her sister-in-law's free will? Or refuse the two most powerful alicorns in Equestria?
The best thing to do, Cadence decided, was to look at this logically. Flurry Heart had been at Sunburst's for just five minutes when she retrieved her. She hated to say this about her daughter, but Flurry was like an emotional support animal for her.
So, Luna wanted to get with Twilight. Understandable. But Twilight was in love with another mare, and this would be no jump-start like her magic usually did. This would be taking Twilight out of love with one pony and into love with another. She usually just helped fighting couples or two shy ponies with a mutual crush (she would never tell Dash and Shy what she had done to get them dating). But this...this crossed the line. Or did it? The Intertwining was pretty much true love, sure, but it happened at the very beginning of a relationship between two ponies meant to be together. If they broke up, it would be nothing unusual, given they would have been dating for a matter of days...everypony would think it just hadn't worked out. And Luna was an amazing pony. Twilight would be in good hooves.
Cadence sighed. She had to make a choice, and she thought she should do it. It wouldn't hurt anypony besides maybe Starlight Glimmer, and she would be also under the impression it hadn't worked out.
"What is this?" The voice of her husband rang out. Cadence looked up to see Shining holding the letter from Celestia. "You aren't considering this, are you? If my sister has fallen in love, it's not okay for you, or Celestia, or even Luna, to meddle with it."
Cadence sighed. "Yes, I am."
Shining lowered the paper, his knees starting to weaken. "I never thought...I thought you cared about...Have you done...I can't believe..." He stopped even trying to form sentences. He walked away, not even glancing back.
Twilight and Starlight were in the library, Twilight avidly reading, and Starlight lying in a pile of books she'd barely touched. Starlight was practically asleep when there was a popping sound, and suddenly Shining Armor was there, looking dejected. Twilight immediately ran over to him, and Starlight did a wacky accurate Sunset impression, hair messed up, eyes barely open, horn at the ready in case there was some monster barreling through the castle.
"Shining!" Twilight exclaimed, giving her brother a huge hug. "What in Celestia's name are you doing here?"
"In fact," Shining said, "it's because of Celestia's name that I'm here."
"What do you mean?" Twilight asked worriedly.
"Luna has a crush on you," Shining Armor said.
"Obviously," Starlight said, finally waking up and combing out her hair with her magic. "One, Twilight's amazing, and two, everyone knows that. What does that have to do with anything?"
"Luna saw you guys go through the Intertwining, whatever that is," Shining said.
"It's kinda like a less dramatic version of your and Cadence's Intertwining," Starlight said, "which you went through when you got rid of the changelings in Canterlot."
"Ah," Shining said, barely listening. "Anyway, Celestia found out and sent a letter to my wife, telling her to use her love magic on you, Twilight, to make you fall in love with Luna."
"Okay," Twilight said without worry. "She said no, so I don't need to worry."
The dejected look on Shining's face, and the spiteful way he said "wife" gave it away. "Oh no," Twilight said. "What will I do! I love Starlight! I don't want to be in love with Luna! I mean Luna's great, but as a friend."
Starlight smiled weakly. "I think there's only one thing to do." Starlight took a piece of parchment and a quill with her magic.
"What are you doing?" Twilight asked.
"Telling Luna she can't come to our sleepover."
"Don't do that! I invited her because she was hurting. This would be even worse. And we could just put up a magic shield, so no outside magic can get in."
Starlight sighed. "I suppose we could do that."
Twilight and Starlight put their horns together and cast a white shield around Twilight's castle. "That should hold," Starlight said. They added a kiss for good measure. They then turned to Shining.
"Thank you so much for warning us," Twilight said. "Who knows what would have happened if you hadn't."
Shining Armor smiled. "My pleasure," he said. "You've found a fine mare, little sister."
Twilight grinned. "Sure have!"
"Please tell Cadence about the shield," Starlight said. "Tell her not to even try, because she won't be able to. Tell her I'll protect Twilight."
Shining Armor sighed. "I will, Starlight. But I don't know what to do. I thought I knew the mare I married, but now I find out she has no sense of morals."
Twilight came up and gave Shining Armor a hug. "She probably was torn and came up with some sort of flawed reasoning for what she planned to do. She probably didn't want to. You should talk to her. I'm sure you two can figure it out. Cadence is a good mare. Think about how well she rules the Crystal Empire! She just made a mistake."
"Thanks, Twily," Shining Armor said. "I'll talk to her. But I'll make sure Flurry Heart is there." He grinned and leaned into Twilight. "She's a great emotional support animal," he whisper-said. Twilight laughed, and he popped out of the room.
Starlight gave Twilight a big hug. "You sure we'll be okay?"
Twilight smiled gently and wrapped her wings around Starlight. "Nothing can break us," she whispered. "We'll be okay, I promise."
Luna was sitting on her bed, frowning. "How are you going to get us together? It better not be with magic. I don't want to take away Twilight's free will."
"Absolutely not," Celestia lied. "The sleepover's tomorrow night, though. You better be ready."