"All right, darling. I've asked for an identification on that cutie mark and I've come up with this." The alabaster unicorn pulled up with her magic a sheet of paper with a photo of a unicorn with an orange coat and fuchsia mane.
"So this is our mathematician?"
"I believe so, given what you told me. Her name is Crystal Charmer, though her original name was Math. We don't have more on her original name than that. This photo was taken very recently after she was a suspect in another robbery." The picture did look surprisingly like a mug shot.
"Another?"
"She moved to the Crystal Empire when she was a filly and earned her cutie mark helping the EBI find the real culprit in a robbery she was accused of committing. She reminds me of you, dear, so I wonder why she decided to go with 'the bad guys' as you so daintily put it."

"What were these robberies of? Banks? Do you even have those here?"
"Yes, we do, darling. However, they weren't bank robberies. They were robberies of universities. Stolen items included not-yet-hatched griffon and dragon eggs."
"Who would steal eggs? Mythical creature eggs or otherwise?"
"There is an extremist group that believes dragons and griffons are equal to ponies since they are intelligent and sentient life forms as well. What this group does not know, apparently, is that these eggs would not have been able to hatch on their own, given that the mothers were unable to care for them. Ponies with majors in biology have made it their project to hatch these eggs such that it has become a staple over time, even going as far as being the entrance exam for Princess Celestia's school for gifted unicorns!"

"If there's one thing I've learned from what we've done back home, it's to never underestimate the mind's ability to rationalize the irrational. And that's one of the reasons why I prefer math: it's impossible to rationalize the irrational."
"I might just become a mathematician thanks to you."
"That would be great. But back on topic, is Crystal Charmer a part of this group?"
"No, and according to this, she helped the EBI catch some of its members!"
"Then I'm wondering the same things you are. Why would Crystal sign on to help these ponies if she's helped the EBI in the past?"
"She was arrested…"
"And when somebody feels wronged, they'll act illogically… I need to go. Thanks, Rarity!"
"Um… not an issue…?" The unicorn shrugged as she watched Charlie run off to his cave of chalkboards.

Charlie corralled all of the five as well as Amita and Don in the throne room. There he explained about Crystal Charmer's case and while he was at it, a good bit about game theory. Everypony but Rainbow and Applejack got it.
"What don't you understand?" he turned to face the two.
"Ah just don't get that y'all can just tell me what somepony's feeling with a bunch 'a equations. Just feels wrong to me."
"I don't get anything. At all. I mean, I understand the part about how she's on the side of the bad guys and we don't know why, but all that history stuff is boring. Oh, and I understood the math bit too."
"It's okay if you don't know the history, Rainbow. That's just what gets us to the point, and you get that. I'll explain game theory to Applejack if…"
"Can I do this one? PLEASE?"
"Okay."

"All-righty, AJ. So it works like this." Rainbow got ten bits and placed them in Applejack's hooves. "Give me however many you want and you can keep the rest."
Applejack gave Rainbow two bits.
"Seriously AJ?"
"Ah need the money, okay? Make yur point."
"Alright. Now, I can refuse this if I want to, and neither of us gets anything. Now I'm going to do that, 'cause if I only get two bits I want to get revenge on you, even though it hurts me in the process. That's what Charlie's talking about with this game theory stuff. Kay?"

Rainbow put all ten bits away and Applejack said, "Okay, Ah can see somepony doing that."
"Everybody understands what I mean now?"
"Yeah."
"Thanks Rainbow, that was helpful."
"No prob, Charlie. As I said, anything I can do to help."
"Hey, you didn't call me 'Chuck' or 'egghead' that time!"
"Uh… well I meant… um…"
Pinkie giggled. "Hey Dashie, you're blushing!"
"I-I am not!"
"Are you all such terrible liars?"
"Rarity isn't!" The pink pony giggled again.
"What?! How uncouth! I am a terrible liar! Who said I was a good liar, Pinkie? Who? I… I am going to sue somepony for this! I don't know when… and I don't know how… BUT BY CELESTIA I AM GOING TO SUE SOMEPONY!"

"I'll have you all know, I am engaged!" He turned his nose up like somepony from Canterlot.
Amita smiled and added, "Yeah, to me!"
"Lucky…" muttered Rainbow. Luckily for her, Pinkie was too busy going gaga over the happy couple to even notice her.

Twilight sighed. "Charlie… I suppose… you are finished… here?"
"Oh. Yeah. And we'll get right to work on tracking down Crystal Charmer."
Rainbow flew out quickly before Pinkie could make fun of her any more, a lingering bit of crimson on her cheeks as she headed toward the library. All the rest walked (though Pinkie bounced after the rest) back to their rooms, even including Applejack. Everypony supposed she'd come too close for comfort in the near-dying category.

By the time it was time to set the sun and raise the moon, Don had come back from his field day with the EBI and Charlie and Amita had come up with a few hot zones for where Crystal Charmer might be. After the sun was set they heavily expected the clip-clop of hooves down the hallway as Rainbow made her way to her bedroom, or at least the gentle beating of wings. Silence.

Around 10:00 p.m., Charlie got out of bed and walked down the hallway to the library to remind Rainbow to get some sleep. He thought he saw a cloaked pony figure run silently into the dark library, but then again the place was dark and the only illumination was created by his horn. He turned the corner, looking into the library as he announced,
"Rainbow, you should really get some…"
The unspoken words died before they made it out. He was so shocked that even his magical light flickered like a candle in danger of being snuffed out by a strong breeze. Rainbow was laying near-unconscious, both wings forcibly broken near the joint and badly bleeding all over the crystal floors. Her face was stained with blood, sweat and tears; she'd obviously been hurt very recently. A meek "help…" escaped her lips.

Charlie rushed over and screamed down the hall something, even he didn't know what exactly it was but it amounted to 'Rainbow Dash is hurt badly, somebody help her!'
"Keep breathing, Rainbow," he told her.
"Y-Yeah… I- I k-know that…" A shiver ran down the mare's body, followed by an unspoken scream that Rainbow wouldn't allow herself to utter.
"It'll be okay, hold on. They're coming."
"Who's… t-they?" Then she went cold and started shaking, an utterly terrified look in her eyes as her pupils dilated a huge amount all of a sudden. "Wha- What's happening…?"

Suddenly the realization struck him that, save for (maybe!) Discord, he was the most powerful pony in Equestria. He had to know how to do this.
"Hold on, Rainbow. Hold on."
He closed his eyes tightly shut, if his memory was a file cabinet he'd have tossed it across the room by now trying to find something. But then again, he'd recently been borrowing several others' cabinets. Namely, Celestia's and Twilight's. THEY had to know something… anything.

Rapidly he found a spell he thought would work. He wasn't certain but it was of a high probability and that's the best you can get. As fast as he could he cast the spell, though he didn't even hear the sound of two ponies running down the hallway and turning the corner into the library and the resulting shock of those two ponies as they saw that he was hovering a few inches above the ground without beating his wings combined with the shock that came with Rainbow's current… state.

Amita and Don didn't stand there and be spectators for very long. A few seconds after they ran through the door, Amita rushed over and pushed all her magic into the spell as well. And, fully aware of what he was doing (that being magic), Don did the same. Rainbow was swept up in their collective aura, some of which wrapped around her wings like shimmering bandages and seeped through her skin. The pegasus mare's body hung limply in the air as their collective aura pulsed magical energy into her. Growing more tired by the second each of the other two thought to Charlie some version of "We can't go any further, she's gone."
"I didn't hear that." Charlie thought back defiantly, shoving even more magic into Rainbow.

There was a loud gasp. All three opened their eyes to see Rainbow open hers, looking somewhere between surprised and terrified. Her fear-stricken eyes met Charlie's and stayed fixed there for a good while. Slowly but surely less and less magic was required to keep the pegasus alive. Her wings began beating out of habit like they should, not one faster than the other, rhythmically unwavering. She landed and soon afterward the three had stopped magically floating. Don and Amita each ended up just sitting down where they were to recover from the dizziness. Charlie nearly fell over running to ask Rainbow if she was alright.

"Heh… yeah… I'm- I'm okay. T-Thanks to you… that is…"
"Not a problem. You're sure you're alright?"
"I was… dead."
"I know! That's why I'm…"
"But I'm better now." There was a look in Rainbow's eyes that he just couldn't place. She looked nervous, but also vaguely excited… Then she leaned over and gently kissed him on the cheek.

Amita was horrified and she sat there in shock.
"I've… kinda wanted to do that for a while now…" She was still blushing slightly as she turned to speak to Amita. "Listen. I know you two are engaged, I know how much of a shock that had to have been but I had no way of saying this if I hadn't. It also… kinda helped me out. So hear me out here, okay?"
Dumbfounded, Amita simply nodded.
"Kay. When I first saw you two together I was really jealous. I thought he only liked you 'cause you met 'im first. Now I see that I was caught up in my jealousy and didn't think, and if there's one thing you have to do with him, that's thinking." Rainbow nodded to herself, reconciling her words. "And to both of you: never, ever stop loving each other. Cause if you do, I'll come to your world, wherever that is, and I'll kick your flanks."

Amita smiled and walked over. "That took a lot of courage. Though I don't… agree with your means… your point was well-intentioned. Thank you. And don't worry, we won't." She walked over to her fiancé. "Right?"
"Oh. …Right."
"Is that a blush I see?"
"…Of course not!"
As Rainbow flew out of the library toward her room she turned for a few seconds to say, "Are you all such terrible liars?"