Morty knows he shouldn't be screwing around with multidimensional shit. It's dangerous, it's impractical, it's blah blah blah. But it's a potential key to unlimited energy, how does nobody see that? He's built a dimensional siphon (it kind of looks like a cardboard box with a funnel and a TI-84 taped to it, but it damn well works), keyed in the dimensional coordinates to a random plane, and by God he's going to use it.
He flips the switch and waits for the energy bar to fill up.
It does! It fills up very rapidly. Then it explodes, along with the box. There's rather more smoke than there should be, and once the smoke clears someone is standing there.
"Oh dear," Morty says faintly.
"I'm favorably disposed, anyway, I don't know her overwhelmingly well - I'm just not a huge fan of mocking her behind her back."
"Ah, Lizzie. Speak of the devil."
She spares him a withering glance. "Snodgrass. Well met, profane."
He grins.
"Seeing if I can teleport through wards. Presented in some order to ensure that if I get a headache it's a little one."
(Martin makes very quiet nyeh, nyeh, nyeh sounds. Elyzia declines to notice.)
"I don't think I mentioned this to anyone here yet, but I do have a sensory component to my power, sort of, and the interiors of those circles past this one fail to exist according to that sense. All the way to the ceiling, or I'd suggest that I could teleport to just above the failing-to-exist part and see if I fall in."
Elyzia nods. "Much as I suspected. So it takes a fairly significant effort to keep you out, but it is certainly possible. The difference past that point is the amount of intent worked into the casting; there is an amount of 'adaptive' magic telling the ward what it should keep out, instead of a predetermined set of parameters. So even though you are not from this world, it still 'recognizes' what you are doing. Good, good."
"Well, that's inconvenient for me and my budding love affair with the magic library, but probably useful in the long run if it means my magic stuff will interact normally with gemini at home."
"I believe that you now know five people who can open the door for you already, or six if you count Headmistress Carson. If you find that insufficient, I can make you a magically unique nametag which you can use to solicit entry from magical passers-by. And I should note that the wards on the department proper are below that level, so you can teleport just outside the door and wait."
"I don't love having to inconvenience people, and I've gone and gotten used to being able to flicker anywhere I please on an eighth of a second's notice. I'll deal."
Armed with her shiny new card, Bella goes about her business. She gets a phone and a laptop and an alarm clock and textbooks for her upcoming classes and a backpack and a wallet. She reads books and the internet, and eats cafeteria food, and says hi to the people she's met and various others, and bugs them for entry into the magic library to read more books. She practices meditation (she gets into the habit of doing so after lunch and dinner, when she's already managed to wrench herself away from reading for a moment), since that has apparently already given her a wee smidge of magic and can't hurt. She talks to Alli, and through Alli, her parents; she gets that letter to the Gemini schools about her educational arrangements written and sent.
She completes her homework assignment. (There is so much magic!) Eventually, she narrows it down. Her basic, cheap intro spell list for herself contains:
1) A silencing illusion, which will work to make her inaudible to people besides Alli, when she twines, unless she very much misses her guess;
2) A light illusion, for obvious flashlight-replacement purposes and simple sillhouette-drawing;
3) Small fire conjuration;
4) Small fire extinguishment;
5) Freezing quantities of water;
6) Calling up small breezes;
7) A spell to braid hair (Alli insisted, she thinks it's hilarious);
8) An illusion that will temporarily blank a page of notebook from view;
9) A dish-doing spell (too specialized to be really useful, also an Alli suggestion);
10) A spell to clear dust off a surface, which Bella strongly suspects will also work on ash.
Her ambitions list - since it turns out that defensive mind magic mostly takes the form of "if you get the hang of wrangling your Essence this naturally comes with the side effect of being able to win at defense in mental combat" - includes several healing spells, the immortality Circe mentioned, interdimensional transit, wards, a more involved defensive measure for her notebooks, and how to make cut-anything blades and unbreakable cables she'll be able to sell for industrial uses if she runs out of arbitrage to do.
Armed with this result, she pops to just outside Circe's doors precisely one minute early on Sunday morning.