@craig: Yeah, what Aegis said

What happened is that Thryn was knocked winded to the ground during the battle. Presumably he didn’t get up, and Calahan and Xandax left him there. Calahan took Llira captive, and now she’s in the hands of the Black Helm being interrogated. What Thryn does next is up to you. You can abandon her or choose to try to save her. Just remember that there will be suspicions if you go back to the Shadow Thieves without her.
Does that help? I’ll go ahead and get Thryn back on track.
@Magus: I'm going to assume you meant the invisibility was temporary, if not, we can work it out some how.
@Aegis: Actually, it was not meant to be temporary (it was supposed to have a very long duration, and not dispellable by ordinary means). It was to be a parting jest, if you will

It doesn’t really matter, but I thought I was clear enough: “He had a sinking feeling that the concealment wasn’t temporary...” When I say a character has a gut feeling about something, it’s usually for a reason
* * * * *
Thryn laid dazed where he had fallen, head throbbing and struggling to breathe. He vaguely heard Xandax and the other guy’s footsteps recede, and a glance in that direction revealed Llira in tow, captured. The other thieves scattered, presumably heading back to Athkatla, leaving Thryn for dead. He waited for everyone to get out of sight before rising. Then he too headed back to Athkatla, bruised and battered but no worse for wear. Though you just never knew with blows to the head...
* * * * *
Upon arriving back in the city Thryn didn’t know what to do. Llira, his superior in the Shadow Thieves, had been captured by the Black Helm. They had probably taken her to their headquarters in the Government District. But, even if he wanted to get her out, it was easier said than done. One slip and it would be all over.
Dusk came and still Thryn wandered through the streets, no longer foreign and unfamiliar. He didn’t even know how he would get back in contact with Magus. Maybe he could help somehow...
“You look pensive, my friend,” came a voice from behind.
Thryn whirled in surprise. His keen ears hadn’t detected anyone’s approach.
A black-robed mage with dark, sable hair stood before him. But something vaguely familiar danced in his eyes, and he felt he had met this man before.
“You have indeed. But wearing my true appearance would attract too much attention. I had to alter Void’s form too, much to his embitterment.”
The name of the unearthly hakeashar brought instant recognition.
“Magus.”
“One and the same,” Magus replies, bowing slightly. “But I didn’t seek you out for idle banter. I’m holding another meeting in the Copper Coronet to compare what everyone has found out so far. I expect you shortly.”
Magus disappears before Thryn can respond.
* * * * *
Void shuffled through file after useless file. Didn’t the Cowled Wizards have anything better to do than document every single boring order or mundane occurrence? For the Gods sake, and these files were only from the past few days! The place where they stored the rest of this trash must be the size of a small city.
In his irritation he almost passes over the unexceptional, everday-seeming order:
Notice to those concerned:
Preparations for the attack in coalition with the Black Helm proceed according to schedule. The date previously set will remain unchanged.
Reminder: The Black Helm has requested for security reasons that all such documents as this be disposed of immediately after being read. Please satisfy our rather excitable allies and comply for the time being. They are beginning to make quite a nuisance of themselves.
Grand Secretary to Corellan the Wise
Leonid Alganthan
Intriguing. What were the little wizards up to? It was important enough that no records were supposed to be left behind; apparently not a light task for the obsessively orderly organization. The agony of destroying precious records must have caused more than a few to lose sleep, Void thinks with a feline smile.
The door suddenly began to swing open. Void quickly jumped under the desk, using telekinesis to quietly shut the file drawer. Requiring merely brute force, it was much easier than picking the lock had been.
The High Wizard sat down at his desk. Void was forced to perform some acrobatics to avoid bumping his feet.
“I wonder what this is about?” the wizard mutters
Void hears the snap of breaking sealing wax.
“Impossible! We can’t just attack tonight! Spells have to be prepared, briefings must be conducted! By holy Mystra, this is the blasted Shadow Thieves we’re dealing with! Such a major operation doesn’t magically fall into place! There must be some mistake!”
The mage stormed out of the room in an agitated huff, leaving Void’s curiosity piqued. Jumping back into the chair, he found a letter lying skewed on the desk.
Notice to those concerned:
The date for the previously planned joint assault has been moved up due to circumstances beyond our control. The attack shall commence tonight at 24:00. Thank you for your cooperation.
Grand Secretary to Corellan the Wise
Leonid Alganthan
This was no paltry deviant arrest. Something terrific in scale was happening that very night. He had to get back to Magus. Glancing at the clock, he found to his horror that it was already past nine in the evening. He had spent the entire day going through the damn file cabinet!
No time for caution. Seeing the door slightly ajar, Void pushed through and bolted along the wall to the entrance, faster than the eye could follow. Void made himself insubstantial as he passed through the doors, then reformed and ran off into the city as the last light of dusk sank behind the horizon. Linked by the special bond between mage and familiar, he made a beeline straight towards Magus’s position at the Copper Coronet.
* * * * *
@all: I would write a little more (specifically initiating the meeting at the Copper Coronet), but I’m out of time. Besides, I think that's enough for one post

You guys can go ahead and start the meeting.