In the library, events resembled a quiz show, if a quiz show was filmed in a library without any annoying show biz distractions, and nopony was filming it. So there were no giant display screens, no studio audience, no noisy buzzers or flashing lights.
But there were lots of books! It was like somepony decided to make a special quiz show for Twilight Sparkle. Luna was sad she hadn't thought ahead to invite the Princess of Friendship With Book Benefits, to watch and cheer her on.
With the librarians' help, Luna had Celestia look inside randomly chosen books on ancient history, technology, arachnography, etc., and challenge the Moon Princess with difficult questions. Luna demonstrated her superbly unimpared, unfaded memory of nearly everything that had happened thousands of years ago.
But if we told you exactly how the Amapones lived so happily for centuries without stallions? Or the original uses for the Indian curry comb? With all the graphic details? We might receive the M-for-Mature rating.
But history is boring, right? So let's censor those dull parts right out! Yay!
In a final surprise bonus round, Luna remembered what she and Celestia ate for their dinner together last Thursday, to show the Moon Princess also knew about recent events.
***
The two alicorns were surrounded by a chaos of books, left in piles and heaps after they'd been pillaged for knowledge. The scene was truly Twilightesque. Librarians vacillated between discomfort at the mess, and joy that these royal patrons had showed so much interest in the Canterlot Library's sacred trust. Around the edges of the scene, an especially proactive librarian tried to inconspicuously snatch a few volumes to start reshelving.
"So, Luna...if you were bound to the moon by both laws and spells, how did you ever get back?"
Luna smiled mischievously. "I was banished to the moon, which is a very boring place. So after a few centuries, without much else to do, I started throwing rocks at Equestria."
Celestia was horrified. "Luna! Don't you love our little ponies?"
"Mostly I do," Luna replied. "But I decided lawyers are a special case. So I threw rocks at legal offices and court buildings. After a while, my aim got really good. It got so I could decide the outcome of a case by hitting the right lawyer on the first try, at least nine times out of ten."
"What happened the tenth time?"
"Usually, nothing much. After a while, lawyers and judges got so used to my hobby that I could hit a spot only a few hooves away from them, and they wouldn't even flinch.
But I did throw ONE miss I was quite unhappy about. Fortunately, my dear Celestia is an alicorn and is practically immortal."
Celestia gave Luna a dirty look. "So YOU'RE the one who half-wrecked the Castle of the Two Sisters?"
"I'm so sorry. I never meant to hurt you. Well, I guess I didn't much hurt you, but I never meant to really annoy you by knocking down the castle's roof around your ears either."
Celestia sighed. "Well, I guess if I remember that you were always aiming for lawyers, I suppose I can maybe forgive you."
"While I was aiming for lawyers, that wasn't only as a public service," Luna admitted. "By attacking the legal system, I eventually caused so much disruption, ponies forgot they were supposed to regularly renew the spells binding me to the moon. A few hundred years later, I was able to get free!"
"But...you returned as an evil villain threatening everypony!"
"There was one thing I hadn't thought about, when I returned to Equestria. The spells binding me to the moon were gone. But there were other spells which hadn't weakened as thoroughly yet."
"Spells making you behave evilly? Oh, my poor, dear sister! To be forced to behave in such a manner!"
"No, illusion spells. As part of the triple-strength full custody award completely disrupting our mother-daughter relationship, illusion spells had been cast that would make me appear an evil monster."
"But when you finally returned to Equestria, you threatened me and kidnapped me! Threatened to destroy me!"
"They were very high quality illusion spells. Let me tell you, it's really annoying to watch illusion spells running around pretending to be you, doing all sorts of evil mischief in your name. And meanwhile, I was jumping up and down yelling, Look over here! That isn't me, this is me! But nopony could see or hear me."
"It does sound terrible. If perhaps not completely plausible."
"I guess I should understand if you don't fully understand, Celestia. After all, illusion spells nowadays aren't what they used to be."
"Why not?"
"Because for centuries, the most deceptive unicorn magicians, who were best at casting spells of illusion and brainwashing, and making other ponies believe their lies? They spent a lot of time arguing cases in court, where rocks kept falling on them. So eventually those particular Dark Arts lost all of their skilled practitioners."
"Ah, yes," remarked Celestia, "I must not forget your centuries-long efforts to reform Equestria's legal system. If that's what we should call your destructive rock-throwing hobby. But at least now I understand why our legal system was so unlucky for several centuries."
Luna said, "I'm so happy that you and your assistants finally thought to have the Elements of Harmony brought to bear on my case. Most divorce verdicts are the result of angry bickering. The verdicts are permanent embodiments of that bickering. So when you focus the forces of Harmony on them at full strength? It's like a friendship laser cutting through butter! Oh, I loved it so much, watching you destroy a thousand years of legal precedent!" Luna squealed with joy and clapped her hooves together.
Luna smiled benignly. "Since the Elements work so well on court judgements, I've been thinking about how useful they might be in international diplomacy. Not to mention wars. We could become practically invulnerable, if countries didn't even want to attack each other!"
Celestia's eyes filled with liquid pride. "That is a very good idea. I am so proud of you."
The ponies embraced, as Celestia said, "There's only one way I could be any prouder. If only I knew for sure you're really my mom."
"Wait the hay!" Luna said. "If only you knew for sure? What about the legal documents? Taking over an entire library to put me through tests that I passed with flying colors? I even knew what we had for dinner last Thursday!"
"You make a good case. But it still hasn't been proven."
Luna's eyes filled with steely determination. "I can think of one more way to show you the truth. If you say no to this plan, you'll be rejecting everything your reign is built upon."