You see an opening and press your attack.

The mare takes another step back, this one completely obvious. “I-I heard something and saw you three. I knew you weren’t supposed to be off by yourselves, so-“
“And how did you know that?“ Diamond Tiara steps forward, “Did somepony- say, maybe a princess- tell everypony they had to stay together?“
“Y-yes. We were-“
“So…“ Diamond Tiara interrupts and looks up at the ceiling, while slowly walking toward the pegasus, “What you’re saying is…“ She swings her head back down and stares the nervous mare down, “You deliberately disobeyed a princess.“
The mare recoils as her eyes go wide. Silver Spoon gasps, evidently having finally caught on, “That-That’s treason!“
“No!“ She argues back in a panic, “I wasn’t! I was worried and-and- oh Celestia!” She drops to her stomach and covers her head, “I don’t want to be banished and then thrown in a dungeon in the place that I’m banished to!“
Diamond Tiara lowers herself to maintain eye contact, “Well neither do we! So you keep our secret and we’ll keep yours!“

Seeing the cowering mare slowly nod in fear makes you feel bad. But you have to admit, it was effective. She says her name is Blossomforth. You aren’t sure what to tell her, though. If you just let her go, there’s no way she’ll really keep quiet.

That’s a pretty huge risk- talking back to an adult. But, you don’t suppose you can get in much more trouble than you already are. You take a deep breath, collect all of your courage, puff out your chest and take a step forward, launching your accusation.

“I was invited!“ The mare replies, pointing to herself. “Princess Twilight Sparkle invited me to tour the castle because I was on the jumbo tornado team! Anyway, you three weren’t with the tour group, so I know you aren’t supposed to be here!“

For most fillies that would be the end of it. She’s in the right; you’re in the wrong. Game over. Hang your head in shame. Start playing Taps, because you’re dead. But, you’re not most fillies. After she pointed to herself, when the mare put her hoof down, it was a step back. She’s unsure of herself. Unsure how to act or what to do. There may yet be a way out of this.

“Of course I’m fine! Why wouldn’t I be?” Silver Spoon comes out from behind the boxes and marches toward you. “What? You think you’re one of us now? You think we’re all friends just because you’re here? You think I care? Well I’ve got news for you- I don’t care! And you’re not allowed to care about me! Do I make myself clear?!”

Silver Spoon breathes deeply and stares you down. Some ponies might be fooled into thinking she’s furious. But there was a catch in her voice. She’s on the verge of breaking down and crying. You’re not really sure where to go from here. But either way you never get a chance, as Diamond Tiara stops in the doorway.

“You two only got this far? What were you doing? Braiding each other’s mane?” Diamond Tiara pauses, as though she’s actually expecting an answer, but continues when one never comes. “Whatever. Like I said, it’s probably not down here anyway. Now come on. I found the stairs.”

The three of you walk in silence to and up the stairwell, which evidently does exist, exiting into a hallway. Diamond Tiara spots an open door and ushers you and Silver Spoon inside.

“I don’t recognize where we are… yet.” Diamond Tiara is quick to add in that last part.
“Well, lets see…” Silver Spoon starts to draw in the air with her hoof, “If the main stairs were here… And we were back here… The stairs would have came out here and we-”

“What do you three think you’re doing?”

The voice makes all three of you jump and spin around! An off-white pegasus with a pink and green mane is standing in the doorway! You can hear your heart pounding in your ear! What do you do?!

Silver Spoon answers from behind the boxes, “How would I know? And what do you care? You’re not even going to be there.”

You weren’t invited this year, for obvious reasons. But the way she said it, and exhaled at the end, sounded like she was going to say more, but stopped. Which seems… odd. You can’t think of a single moment where either Silver Spoon or Diamond Tiara showed a drop of restraint.

Your sense of timing is telling you that you’ve probably got one more try at this before she gets annoyed and starts to ignore you.

You don’t remember why, or if she was even talking to you, but you remember Lyra once suggesting that Harmony is alive. That the concept adapts as time passes, and in that way, it just knows things. Since the powers of Harmony created the castle, interior and all, it would make sense that it just knows how to lay everything out safely.

Still, it could be an interesting source of conversation.

“I don’t care.” Silver Spoon dully replies as she disappears behind a stack of boxes in a storage room, “I don’t even know why I’m here. I should be getting my beauty rest for my birthday party tomorrow.”

That went about as well as you expected, but maybe a different subject is worth a try?

You don’t want to. You really don’t want to. But, with a sigh, you walk over to the window and extend a hoof to help. First, with Silver Spoon pushing from below, you pull in Diamond Tiara (who needs to lay off the nachos and cake if she expects somepony to lift her) and then the two of you pull up Silver Spoon. Without so much as a ‘thank you’ from either of them, they dust and straighten themselves out and peek out the doorway.

“This should be the backside of the first floor,” Diamond Tiara thinks aloud. “Straight ahead should be the main foyer. We can’t take the staircase, obviously, but it would be a fire hazard to only have one way up or down. We’re looking for a servant’s stairwell to reach the main part of the castle.”
“What if it’s stored on the first floor?” Silver Spoon asks.
“That wouldn’t be very secure, but you two check the rooms while I look for the stairwell.”

The three of you head right out of the doorway, with Diamond Tiara quickly heading further and further away. Leaving you alone with Silver Spoon to check out the rooms.

You disagree about the plan, but you really don’t want to be around these two.

After taking a few steps back and sizing up the window, you burst into a sprint and kick yourself up the wall. You manage to land your body on the sill and pull yourself in the rest of the way. Not as graceful as you’d imagined, but task complete.

You hear Diamond Tiara from outside, “Nice job! Assuming nopony heard you, of course. Now pull us up.”

Pausing to check your surroundings, you notice the room is empty and undecorated. This part of the castle must not be in use yet. There’s no door and the hallway beyond is L shaped; going to the right.

Outside, you hear Silver Spoon speak, “What is she doing up there?”
“Probably checking to see if the coast is clear. That’s what I’d do.” Diamond Tiara replies.
“What if she just left us?”
“This is for your birthday; she wouldn’t do that. Relax.”

That’s right. This was for her birthday. They both gave you presents last year. And you were invited to Silver Spoon’s birthday party last year too, before you punched her. They’re mean, hateful ponies. But would leaving them behind, after they helped you find the safest way inside, make you any better? This could even be your way of making amends to Silver Spoon for hitting her.

“Besides,” Diamond Tiara continues, “If she does, we’ll make her life completely miserable.”

Well, that’s always a strong motivator too.

Either way, this is your last chance to suffer through Diamond Tiara and Silver Spoon coming along, or ditching them, and whatever retribution comes with that.

By the time you catch up, the two fillies are already mid-conversation below one of the windows.

“Well,” Diamond Tiara rolls the map back up again, “According to this, that’s the best way in. It offers the most cover.”
“So we don’t even need it anymore? Wasn’t this a waste of time?” Silver Spoon, completely aware that you’re there, points at you without looking. “It’s not like we had to wait for her.”
“It pays to be prepared.” Diamond Tiara tosses the map into the bushes. “Now help me up.”
“Excuse me? It’s my birthday-” Silver Spoon pauses to judge the position of the moon, “Technically today! You give me a boost!”
Diamond Tiara scoffs, “Well that’s not going to happen.” She points to you. “Give us a boost, and we’ll pull you in from inside.”

Can they really not make that jump? You’re positive you can. This could prove an ideal opportunity to leave those two behind. But, if they can make it inside, or even if they can’t, they’ll likely find a way to sabotage you. Or at least try.

Aunt Bon-Bon says kids are always very melodramatic. Lyra says that most adults forget how dramatic it is being a kid.

Double-cross sounds a little harsh. You just want to get away from them.

A simple enough question. You ask.

Berry Pinch forces through a yawn before answering. “Black mail; why else would anypony be here?”
“I was invited!” Zipporwhill excitedly replies.

Diamond Tiara and Silver Spoon return, looking annoyed.
“Aren’t you two done yet?” Diamond Tiara looks square at Berry Pinch, “I thought you said this wasn’t going to take very long.”
Berry Pinch walks towards Diamond Tiara, shoves the clipboard into her chest, and starts walking away, “I’m going home.”
“What?!” Silver Spoon exclaims, “If you leave now we’ll-!”
“You’ll what?” Berry Pinch replies over her shoulder, “Map is in your writing-style. I was never here.”
Silver Spoon rushes over to Diamond Tiara and gasps at the map. Diamond Tiara waves Berry Pinch away, “Let her go. She knows this isn’t over.”
Zipporwhill flies over, looking worried, “Where is she going?”
“Don’t care,” Diamond Tiara replies coldly, rolling up the map, “Just like I don’t care where you go. But it won’t be with us.”
Her wings stop beating and Zipporwhill lands slowly, “But… But you said we were having a sleepover!”
“Tsk. I don’t remember ever saying that.” Diamond Tiara puts a hoof to her mouth and turns to Silver Spoon, “Do you remember me ever saying that?”
Silver Spoon taps her chin, “Something about coming over for the night. Nothing about sleeping. Nothing about staying.”
Zipporwhill’s lowerlip quivers and you can see tears forming in her eyes.
“Too bad,” Diamond Tiara brushes past her, “But don’t worry. We’re sure you won’t get in too much trouble when you get home.”
“Come on, Zipporwhill,” You hear Berry Pinch call back. Evidently she turned around and came back. “You can spend the night at my house.”
Zipporwhill quickly flies over to Berry Pinch, her voice still shaken, “But-but won’t your mom be super-angry?”
“Trust me, she won’t care,” Berry Pinch replies and the two disappear into the night.

After watching this scene, you turn around to berate the two bullies for their horrible behavior, but they’ve already walked away toward one of the castle windows.

Berry Pinch is… different. Ms. Cheerilee says she’s gifted. Aunt Bon-Bon says she’s mature for her age. Lyra calls her “abnormally intelligent”. She can act like a normal filly when she’s playing, but beyond that she’s very serious, very careful, and very smart. You have to wonder what forced her to be here tonight.

From Berry Pinch’s perspective, it must look like you’re working with Diamond Tiara and Silver Spoon, instead of for them. You try to explain, but she interrupts you.

“It doesn’t matter now; it’s too late for you to back out.” Berry Pinch stops what she’s doing to look you in the eye. “But you’d better get away from them as soon as possible. You might think everything is sorted out. That it’s fair. But all they’re doing is gaining more and more clout to hang you with. And once they have enough,” She turns back to her clipboard and resumes writing, “You’ll never be free again.”

You gulp hard with a shiver. It suddenly feels a lot colder outside than it did before.

You’re just a kid! You can’t incapacitate an adult guard! You do tell her everything else, though.

“Don’t worry your little head over it, Little Liza,” Diamond Tiara waves a hoof in dismissal.
“Yeah,” Silver Spoon chimes in. “Secrets never remain secret to us for very long.”
“No kidding…” Berry Pinch says with a dejected yawn.
“And it’s not like we’ll be splitting up,” Diamond Tiara puts a hoof around Silver Spoon. “If we leave you alone, you might blow our cover.”
You see Zipporwhill zip over to comment, “I am so very excited for our upcoming adventure!”
“Yeah,” Diamond Tiara rolls her eyes.
“Whatever,” Silver Spoon does the same.

Zipporwhill gives a wide smile and returns to looking into the windows while Diamond Tiara and Silver Spoon take a few steps away, seemingly to talk in private. Berry Pinch glances over at you and stares for a long moment before going back to her drafting.

“Dancing with the devil tonight, aren’t you?”

Diamond Tiara seems to be waiting for you to ask, so you do.

“Oh, it’s really quite brilliant.” She rubs a hoof on her chest and glances down to admire it, “A true testament to my intellect.”
“Except it was my idea…” Berry Pinch mutters under her breath.
“And I picked you to think of something, so that makes it my idea. Daddy says that’s delegation.”
Berry Pinch can only roll her eyes in response.
“As I was saying,” Diamond Tiara turns back to you, “The help is mapping out the back of the castle and guessing at how the rooms connect. It won’t be perfect, but together with our knowledge it should be enough to get us around.” Diamond Tiara leans in close, “FYI, they don’t know what we’ll be looking for. If it is true, the fewer ponies that know, the better.”

You can’t argue with that. Getting caught in another dimension isn’t like getting caught sneaking a cookie. You’d get in at least twice as much trouble!

You have room enough to pack some water. Good thing Lyra buys bottled water. She doesn’t like the taste of tap. You can’t tell the difference.

Another dimension is no place for a dog, so you put out some extra dog food and leave Simple behind. Hopefully you won’t be gone too long. Or somepony comes to investigate.

With nothing more to do, you head out early toward Princess Twilight’s Palace. The sun has completely set by now, but the moonlight is just bright enough to find your way along the empty roads. When you reach the outskirts it appears you’re alone at first, but you see a light shine in the darkness on one side of the castle. As you approach, you realize it was Silver Spoon’s glasses; she was using them to reflect the moonlight as a signal.

“About time you got here,” Silver Spoon puts her glasses back on and adjusts them, “We were starting to think you weren’t going to show!” She turns away and walks along the side of the castle, under the well lit windows. You start to mention that you’re fifteen minutes early, but you’re too exhausted from dealing with these two to argue.

You and Silver Spoon reach the backside of the castle to find Diamond Tiara and, oddly enough, Berry Pinch and Zipporwhill. Zipporwhill is buzzing about looking in the windows and talking to Berry Pinch, who seems to be writing something. Once you get close enough, you can tell Zipporwhill seems to be having the time of her life, but Berry Pinch looks tired and miserable. There are clear bags under her eyes and she yawns two or three times every minute.

Diamond Tiara walks over to “greet” you, “So hard to find good help, and on such short notice. Here’s hoping this little vacay of yours is worth the trouble, for your sake.”

You pace around for a minute or two. You aren’t really sure what to do next. There’s still time to do… something, you’re just not sure what it would be. You could go ahead and meet up with Diamond Tiara and Silver Spoon. But that probably involves waiting, and you’re a little antsy.

If you can’t think of anything, you won’t really have much choice.

You’re not really comfortable with carrying around a weapon. But hey! Who says a knife has to be a weapon?! It’s a great survival tool! You can cut stuff with it and-… Well, you don’t really have much in the way of survival skills. You doubt Diamond Tiara or Silver Spoon do either. Maybe you could find somepony who does?

By cutting an empty paper tower roll and using some a bunch of tape to reshape it, you craft a Portable Knife Holder! You combine that with a Kitchen Knife to make a Safe-For-Travel Knife and put that in your bag! You might not have any survival skills, but you’re as crafty as a slice of cheese!

… That… That probably would have been funnier if Kraft cheese existed in your world.