"Very well then." Slowly, making sure the stallion was still convinced, Twilight took hold of the scale and began to walk towards the platform. "I will be going alone at first, for safety reasons. Starlight can give you a few ideas of what might be on the other side." She turned towards Stone. "I hope that is not a problem for you."
Still breathing slowly, Stone nodded again. Starlight began to approach him, meanwhile looking at Twilight. "Are you sure you're going alone?" she asked.
"You just came back from the desert, it's better if you stay here," Twilight said, setting the scale in place. "I wouldn't want you to get tired." Concentrating, she began to cast the long series of protective spells needed as precaution before traversing a portal. They'd managed to combine most of them, and make it so the different portions only triggered and actually drained most power when the conditions requiring them were met, but it was still a rather complex and relatively taxing piece of magic.
Behind the alicorn, Starlight began to tell Stone Brick of the first time they'd traversed a portal. She conveniently left out the possibility of it blowing up the castle and maybe more had things gone wrong, Twilight noted. Ponyville had probably never been in danger, there were measures in place to contain an explosion to the castle itself, but if a reaction strong enough to overcome even that occurred then it definitely would have taken the town with it at the least.
Shaking those thoughts out of her head, Twilight focused once more on the scale in front of her. She readied her horn, then cast the spell, and a moment later light spread out from the scale in the portals' familiar pattern. "See you in a bit," she said, stepping forward.
The trip through the portal was no different from the usual one. The world on the other side was dark. That was her first impression. Night covered the sky, the light of the Moon shining down over everything. A street paved with stone on the ground, well maintained, buildings in the same condition. Soft whispers and breaths, the subtle clacking of a few hooves.
Twilight looked around her. Ponies, standing still and looking at her. Surprised, like their daily lives had been interrupted, curiously studying the new arrival. Silent. A few dark banners hung from buildings and posts, and Twilight swore she'd seen a pattern like the one on them before.
There was something about the way everyone was looking at her. About the lack of words or sounds. About the colour of their eyes. A castle stood not too far from her position, behind a number of streets and buildings, the top still visible as it towered over everything else. Ancient stone towers and walls, and dark flags waving from posts above them.
One pony stepped towards Twilight. The alicorn stepped back into the portal.
Twilight stepped out of the portal, in the middle of her laboratory. Starlight and Stone Brick looked at her, and worry coloured their expressions as they noticed hers. "Is everything alright?" the unicorn asked, while the portal closed.
Twilight looked at both of them. "We need to talk."