The plan is refined and strengthened, contingencies are set to deal with various ways Thorn could've strengthened his defences, Mortal receives a very interesting email concerning one of their mother's contingency plans—namely that her assets have all been either frozen or transferred to Mortal themself, so Thorn doesn't have access to them -, and when Mortal and Promise judge there's nothing more to be gained from further planning they (eat dinner, sleep again, have breakfast, go over the plan once more when it's not completely fresh in their minds so they see if they come up with anything new, purchase Promise a mobile phone and a power generator to charge its battery in fairyland, eat lunch while Mortal teaches Promise how to use that, and) part ways.
On this side of the veil, Mortal gets to work. The first step: getting at least two safe houses, one for their HQ and the other for contact with the place near Thorn's court. They end up getting five, for redundancy's sake. The main HQ is near Seattle, the other four safe houses are in Greece, Russia, Japan, and Argentina. That, and getting the necessary existing equipment, is the easy part—you end up with contacts of the relevant sort when the bulk of your wealth comes from the kind of thing you can get with sorcery. The hard part is getting the various specific bits of technology that don't exist yet, including the the many types of trap and ammunition they'll need. Processing fairy voices with software turns out to be a dead end—apparently they're weird magical superpositions of sounds that make software go ?!?!?!?!?—but everything else, as agreed upon, can be made to spec nicely enough.
It'll take a couple of weeks beyond the one month for everything to be ready. Mortal hires someone who talks very fast.
And after the ball's going, there's not actually much for them to do with their time. They fret about details of the plan, order more redundant pieces of stuff (especially the to-spec stuff, not being mass-produced means they'd better have a lot of it to start with in case anything goes wrong), and have various antsy and anxious and calm and relaxed and terrified and panicked moods. A month is a long time...
At one point it occurs to Mortal that Promise might've decided to run away and not help, and then they'd never see her again and that would be terrible, and why would it be terrible anyway? It's just some fairy, fairies are evil, one must remember that. Even though she wasn't, of course, she was smart and resourceful and moral and ridiculously hot, and if they never see her again she'll never order them again and the tingly feelings won't ever happen again. Except what the heck, what are they even thinking? The answer, of course, is that they want to see Promise again. Why? To save their mother, of course. The only reason being ordered like that felt good was because Science. Of course. Of course.
The month passes—
"Not over the noise, no, which is why I said Sand would probably not work. ...it's possible Sand can still hear us over the noise, though, with the earbud."
"If Sand even twitches now they know who the mole is. Maybe when someone comes to check him..."
"Yeah, we don't say anything to him until he's no longer stop-ordered. I'm not sure we can come up with a game plan here before... more things happen. And we should think of contingencies that don't depend on these moles, probably."
"If he discovers Sand, he'll probably discover Verve... And in that case I think it's best if we have her get the heck away so he won't know how we actually captured her."
"And actually, should we do that before Thorn actually learns of her involvement?"
"...If at all possible we should disappear Verve next time she's between courts. She's moving again tomorrow, right? He might not have his checks out to where she is now by then."
"Yeah, fair enough, if he finds out about her we can have her try to flee then. Now, hmm, assuming it all goes to heck..."
"Might be able to send Verve on a surgical mission to find your mother if we knew where she was, that would be something at least. But we don't know where she is except by process of elimination."
"Might Verve herself know where Thorn's latest project is? Or where 'the mortal woman' is? Or something?"
And what are Thorn and his sorcerers up to?
They're tearing the place apart, patting down everyone, putting out ears and delivering orders in lights. They'll be at Sand any moment. They're going to find the bugs.
"I don't think we'll be able to wait until tomorrow to get Verve out of there, Sand's gonna be found. Any last orders we could give him?"
"He won't get away if he makes a break for it, they can heal him if you have him bite his tongue off, they'll find the earbud even if he flings it away - no, I don't think he's salvageable or usable anymore." Hmm. "Could your hireling learn a little bit of sign language? We could have Verve sneak out now and go in later with - is there something bigger, more eyecatching than a phone, that'd transmit sign? That she could present to Thorn?"
"A phone wouldn't work in fairyland anyway, no satellites for signal, but yeah I did get something like that, to transmit video, I used it in the little RC vehicle to catch Verve. And it shouldn't be hard to get my hireling to learn how to make the signs necessary to neutralise Thorn."
"We can make Verve turn it invisible herself so she can drop the invisibility on it at the right moment."
"Yes. How long would it take the other fairies to key Verve out of the wards?"
"...to the limited extent that's how wards work, not long, but that just means she has to catch Thorn outdoors."
"Will she be able to? If I were Thorn I probably wouldn't leave that court for... a while."
"He's got to go after Blossom personally, bare minimum, in case she's compromised."
"...hmm. That's a nice window of opportunity, there. Do we know where Blossom is?"