"I don't know why you're bothering," Edie says of the copper-and-verdigris design. "I mean, the rest of it is going to go green too eventually, right?"
"Maybe, maybe not," Emily says stubbornly. "I could coat it with clear paint or something to prevent oxidation."
"Fair enough," Edie says, and returns to perusing her book.
Once they're outside the house, she casts, "Stormwing Flight!" Wings covered in razor-sharp steel feathers spread from her back.
"Wing's of the Mind's Eye." Edie's feathers are crystal, glinting with flashes of color and hints of images, there and gone to fast to see on such small surfaces. And: "Perception Periapt." A faintly glowing orb appear in her hand.
The two sisters take flight. It's a bit of a trek to the mall, but it shouldn't take too terribly long, flying.
Periodically, mirrors appear surrounding Edie, wisps of some kind of vapor flowing out of them and into the orb. It happens more often when they're above large numbers of people. Not coincidentally, no one notices them.
"...I don't like how many hostages he has. And the implications for why someone like that would want to have that many people captive...I'm going to get everyone out I can. You should see if you can figure out what the fuck he wants them for and get his artifact away from him if you can--your powers are better for that than mine."
"True. Alright, just let me--Si Vales Valeo," she casts, swooping down to leave a silver dot on her sister's forehead.
Edie casts the spell too, twisting up to leave a reciprocal mark. "Standard minor injury code applies?"
A number of large mirrors spring into being around her. She considers carefully where each one is coming from, then dismisses them, opens her eyes, points and says, "that way."
They fly for another half-mile, which only takes a few minutes, before landing and dismissing their wings for the narrow corridors. They find the door Janine pointed out on her map, and slip inside under cover of the Periapt.
No one notices the intruders, of course. The corridors may be too narrow for wings, but there's more than enough room to slip past magically oblivious guards.
The maze is... ominous. The walls seem to be made of an opaque purple-black glass with an oily iridescent sheen that pulses unnervingly in one's peripheral vision.
The twins wind their way through the corridors, Edie firmly tracing the path that Janine set on paper and Emily following--she'll split when she sees a likely-looking doorway, but no point in just running off to get lost without a sign it'll be productive.
Emily considers casting a Mass Driver, considers the possibility that the spacewarping is more insidious and she might hurt the prisoners, considers a Shrapnel Barrage, considers that that seems less than likely to be able to pierce the walls, and casts, "Prismatic Railgun!"
A black stain spreads out over the wall from the point where her projectile hit it.
"Third Eye Annihilation Beam."
"Interlopers," he manages to snarl tiredly, and he swings his right hand, backhanding Edie into the opposite wall without actually touching her. The fact that that hand has a profoundly black gauntlet on it with blue stones like the threads in his cloak on the knuckles probably has something to do with it.