Margaret Peregrine is a high school sophomore. Most of the time, she's either at school, at the school robotics club, at the school chess club, or doing schoolwork. Today, she's cleaning out her late great-grandmother's attic.
There's Isabella, lying on a tattoo chair, getting what looks like a runecasting diagram inked on her back.
This is the weirdest way to instantly take pictures with a polaroid camera ever. Margaret glances at the paper, ready to immediately look away again if she had the bad luck to catch Bella changing clothes or something . . . Wait, what? Who's paranoid enough to get a tattoo for what would only be a one-time emergency spell instead of, she doesn't even know, making a reusable artifact version and doing it to all your socks?
Well, in for a penny of creepy spying, in for a pound. Margaret peers at the picture trying to make out the largest runes. It's going to be some sort of escape spell, right? She's got to have made a healing artifact by now.
That . . . is not what Margaret would have picked for a last-ditch one-time bailout spell to have available when someone has stolen all her artifacts, especially given that Bella can fly and has a diagram for going through walls. This is either a dumb mistake or some kind of genius plan Margaret totally isn't getting. Well, whatever, Bella's going to be getting this necklace of teleport as soon as a scry shows her being alone. Time to trace a massive load of scrying diagrams, then try every three hours until she finds a good time.
WHOOPS flip that paper over and then crumple it up and shove it in the bottom of the recycling bin with the entire forest worth of expired diagrams. This is why you scry before you 'port, kids!
She keeps going, though "every three hours" is actually "every three hours when it's not reasonable sleeping hours" because neither getting up in the middle of the night to scry nor watching someone else sleep seems like a fun time.
In the morning she can catch Bella having room service in what looks like a hotel bed.
That seems reasonably interruptible. Now to find a good teleport point. Surely if magic can identify people it can also identify bits of architecture, right? Margaret grabs a location diagram and gets the latitude and longitude of "the point in the center of the hallway outside the door to the room containing the nearest person with the first name Isabella and the last name Swan, which is closest to that door".
Now she just needs the vertical dimension. She scries that same location description, specifying that the camera is to be pointed at the door, and reads off the room number.
Okay, then. With the safeties Margaret put on the teleport, there's no harm in a few wrong guesses; she'll start with twenty feet up and increase it until she gets a value that won't have her intersecting a ceiling. She's already wearing her own rings of invisibility and teleport; now she grabs Bella's necklace, a simple glass pendant spelled for teleporting, invisibility, and durability. She double-checks her coordinates for the hallway, turns invisible--and teleports.
Huh, tall ceilings in here. Now, where's the stairwell? If it's on the other side of the maid, or inconveniently card-access, she'll just whisper "teleport home" and try again at thirty feet.
Then she will reach the third floor by an entirely mundane route, and assuming the stairwell is empty she'll be visible when she comes out.
Room 306: knock knock?
"Margaret. From Seattle." Please don't assume it's a trap and run away, please don't assume it's a trap and run away . . .
"I promise it's just me. And I brought you useful stuff."
"Hi." She looks about like Bella would remember, but slightly frazzled and with her right arm thicker and more muscular than her left.
She looks around to see if anyone is listening, then holds out the necklace and adds quietly, "Want a necklace of invisibility and teleportation?"
"They'd have to know what it was and the keywords--can we talk about this not in the hallway?"