The other mage catches up. "Some low-level spells right before, then - here, look at this..." He doesn't know how to interpret the magical signature, especially.

Leareth frowns at it. :Maybe a conjuration?: he guesses to Nayoki, in Mindspeech. :It could be a Teleport:

:You think she -:

:I continue to think she is almost certainly not in Valdemar, but the tracking-item search should turn that up soon enough, unless she is behind someone else's shields, in which case the search-spell will give us her rough location eventually. Get someone searching the room closely with mage-sight, please. I am going to past-watch:

The spell he can use to view events in the recent past is very tiring and will inevitably cost him an entire morning of productivity on mage-research, but that's fine. It also takes a bit to set up. Leareth starts working on it.

Someone arrives at Nayoki's direction and starts looking around for spell-residue, though Golarion spells leave less helpful residues than Velgarth ones and they're not sure they know how to interpret it anyway. Leareth would do better but he appears occupied. And also still very unworried.

So they can see spells cast. That's not surprising.

She takes off the shield-talisman and sets it down. Then, regretfully, takes off her headband, too, examines herself closely for any other magic.

There's also a very low power and well-concealed but findable scrap of magic on her gown; it proves to be a crystal focus no bigger than a grain of sand, sewed into the lining where she would never have noticed it without combing herself over thoroughly.

Leareth is half done casting the spell when someone taps at his shields, letting him know that Carissa is not in Valdemar or, in fact, anywhere within the range that their highest-powered search can pin down the tracking spells on her. Which means either she's over a thousand miles away, or she's behind very very good shields - the oldest Palace Work Room in Valdemar might suffice, but little else - or she's not in this plane at all.

:Thank you: he sends back, and returns his focus to the past-watching spell.

(To Carissa's viewpoint, it's not obvious what he's doing, aside from 'magic', and he's not speaking out loud at all.)

Carissa examines the gown, and then very carefully slices it out, and then decides she can't be sure she missed one and takes the whole thing off, and then prepares spells for her remaining slots, hurriedly. 

Leareth gets the pastwatching spell up. Like with Farsight, the image is only visible to him, though he can pull Nayoki into Mindspeech rapport to share it with her.

It's been a little over ten minutes. He reaches back with the spell until the moment at which the wards triggered an alarm, then to about two minutes before that point, and then he pushes in more power and watches it with mage-sight as well as he plays forward those two minutes.

Carissa sets some Unseen Servants to work tidying the room, and some Dancing Lights racing about it. She looks cheerful. The Dancing Lights go out. There's a planar spell, third-circle. There's an illusion spell, second-circle. The Unseen Servants continue their work sweeping and moving her books around (it being dark, this is mostly only visible to mage-sight as the magic itself, not the effects), and then abruptly wink out. 

Leareth goes back again to the point where the Dancing Lights went out, and this time tries to specifically keep his attention on Carissa's visible aura of mage-energies - where does she go?

Her aura disappears when she makes herself invisible. Then there is the third-circle conjuration spell. Then there's the second-circle illusion spell. 

Leareth replays the sequence several times in a row. It...doesn't make sense? For one, the third-circle signature isn't powerful enough for a real Teleport, or even a real Dimension Door, the shorter-range version. It's - not impossible, he supposes, that she invented some hyper-optimized short-range Teleport that could work at third-circle, maybe just enough to get her a hundred feet away or so and outside his wards, but - also, it doesn't make sense that she would have cast that and then an illusion. There's not a huge gap but the second-circle illusion spell's signature is definitely after the planar magic.

He's so curious.

:Organize a search for her or for any sign of spell residue within a two-hundred-foot perimeter of the base: he orders to whichever Mindspeaker is nearest. :Anything on the search?:

      :No, not yet:

That's not surprising, the exhaustive search-spell based on the hair sample - which is fresh, he had a Fetcher taking some from her hairbrush every night once she was asleep - takes a long time to cast, and is especially fiddly when done from hair instead of blood. Obtaining nightly samples of Carissa's blood would have been a lot more inconvenient and he judged it not worth the cost.

All right. Focus. Replay the past-spell again; can he see where the illusion-magic is landing?

On the ...wall? Maybe on the wardrobe.

Still holding onto the spell even though his head is aching a bit now - it'll be even more tiring if he has to re-cast it - Leareth strides over to the wardrobe, and this time pays very, very close attention to what his mage-sight can sense there in the present. Is there still any hint of active illusion magic?

He has to look very very very closely but - yes, there's a careful illusion clinging to this dress, or to - something pinned in the dress.

...Weird. He can't figure out what she's playing at, here. (It is also apparent to Carissa, watching unseen, that Leareth is definitely enjoying himself right now.)

     A tap against his shields. :Update. Search-spell - she isn't in Valdemar - she...isn't in the material plane at all...? I'm sorry, I can't get closer than that:

Leareth's lips twitch. :I see. Thank you:

Planar magic. Low-powered. Maybe she could teleport herself to the Elemental Plane of Air or something, just 'adjacent' to this spot, but - that's awfully chancy, it's unclear that even the friendliest other planes accessible from Velgarth would support human life for long, she would have to trust her protective spells a lot and he doesn't think Endure Elements would suffice...

She won't have done anything suicidal, he thinks. Wherever she is, she's fine. Probably very pleased with herself, too.

He takes down the past-watching spell, he's gotten everything from it that he's going to and he wants to be less distracted now.

With a twist of magic, he reaches out and snips through just the right place in the illusion spell to set it crumbling to pieces.

Carissa is relieved that Leareth is enjoying himself and hopes he still feels that way when she's done, which she isn't, she still only knows slightly more than she started with about how he's tracking her. Detect Thoughts would be so informative right now but it doesn't work across the planes.

Well. It's time to get out of here anyway.

She casts Nondetection. Invisibility. Detect Thoughts. Gaseous Form. 

And she leaves the demiplane, which still contains her dress and her invincibility artifact and her headband. She takes her pearls of power and spellsilver. She thinks he can't track her now, and she wants to see if she's right.

Also she really really really wants to see if she can read his mind.

The illusion appears to have been concealing that this rope has an aura of transmutation.

(Unfortunately Carissa cannot read Leareth's mind; he seems to have a very high will save against Detect Thoughts, possibly related to one of the multiple protective magic items he wears all the time; there was the one he took off back when he offered to let her read his mind.)

...What is the rope doing? What does it even mean for a rope to have an aura of transmutation because someone cast a third-circle conjuration spell with some sort of planar effect on it?

Leareth tries to unpin and pull the rope out of the dress to get a closer look at it.

Elsewhere, Leareth's mage still has the search-spell up and is trying to narrow down which other plane Carissa is in right now -

- and the spell is suddenly going nuts and so confused! He still can't pin her down but the spell seems to think that she's now in the material plane and - probably within ten miles?

The rope seems incredibly stuck! To - a particular point in the air? It can be pulled out of the dress but it's still stuck to the air.

Carissa frustratedly leaves the room and looks for someone else to mindread.

Nayoki is standing in the hallway, simultaneously talking out loud to someone and also Mindspeaking someone else further away, and she's not wearing any magic items against Thoughtsensing and isn't paying the most attention she ever has to her shields; Detect Thoughts can get through. There are also a lot of other people who aren't that well shielded but Nayoki seems like the one who's the most in-the-know about what's going on.