Isabella's there, waiting.

The train arrives on time, and people start getting out.

No sign of Sadde.

...

Isabella waits for the next one in case Sadde just missed it.

Nope.

Isabella goes up to the counter and asks if there's a way to find out whether something may have happened at the station her sub was supposed to get on at.

The nice sub at the counter smiles at her and says he can look it up for her if she wants.

Yes please. Her sub was supposed to get on here at this time...

He gets the name of the station and looks something up on a computer. He frowns thoughtfully then tells her his system has nothing on it, everything seems to have been normal. What's her sub's name, maybe he can see if they boarded the train at all?

"Sadde Baldwin?"

He looks it up and—" Apparently they didn't board at all," he says in an apologetic tone.

"...Okay. Thank you for checking."

"You're welcome. I hope everything's alright with them."

"I hope so too."

He smiles, still looking somewhat apologetic.

Isabella goes back to school and does her best to come up with contact information for the Baldwin household.

The school can't really give her other students' contact information, but if it's urgent they can relay a message.

Sadde was expected back on this train and didn't come on that or the next and have they been formally withdrawn or anything...?

They have not, or not as of today anyway. Maybe something came up; she could wait a few days and check again.

Okay.

The new semiquarter starts, and by Friday when they and Isabella were meant to go to the play together they have not yet shown up.

Has Sadde been withdrawn?

Oh! Apparently so, yes, just yesterday.

...Isabella gets Tobias's email from Renée and sends him an email asking if Sadde's all right. Ever so politely.

And Tobias replies that of course she's alright, but she seems to have come to the conclusion that magic school was not really the best environment for her, and asked him to withdraw her. He's sorry about it, and knows Isabella really cared for her, but believes this was probably for the best, implying pretty heavily that she shouldn't expect to see Sadde again.

Perhaps she could trouble him for the household phone number and talk to Sadde? Say goodbye?