The enemy wasn't ready enough to actually hold this first stronghold in a small foothill of the Crystal Mountains, but they were ready enough to make it troublesome to take.
Aeslin had hung back through most of the battle after casting all the wards she could on everyone - she didn't want to use up her channeling strength while they didn't know what was deeper inside - and now that they knew there were some holdouts sealed in the inner cavern, it looked like that had been a good decision. Plus... the fighting so far had been pretty conventional. The enemy had used that new Stronger Sleep Spell that she still hadn't been able to figure out good wards against, but she'd seen it before, and she knew she'd be able to fix those two dozen soldiers as soon as she had some time. Nothing was new; she hadn't seen any more of that secret magic from the Days of Wonder that she knew the Crystal Mountains had somehow found.
(She didn't know how the Crystal Mountains had found that; Queen Elethy didn't know either... It was clear Elethy had some guesses, and Aeslin had some guesses what Elethy's guesses were, but neither of them had actually talked about it yet.)
So, Aeslin tapped Captain Eoman on the shoulder and said she'd be the first into the sealed cavern as soon as they busted down the door.
He looked sort of taken aback, but he didn't object.
For the first half-minute, it looked like a very good decision. Conjured lava, Stronger Sleep, something that looked kind of like a ritual binding for Lesser Fay, and more - she could counter all of those in the moment herself, her two wands waving like a high-speed dance, and bat the Stronger Sleep back on the Crystal Mountains mages who'd cast it. Aeslin was in her element now, feeling one with the magic even if no Elf, spell on joyous spell.
But then the whole floor pulsed under her. It felt something like Stronger Sleep crossed with wandmaking charms crossed with that one time she'd poked at a pocket dimension left from the Days of Wonder(!) - she didn't know how to make a pocket dimension - nobody had since the Days of Wonder -
Her amazement made her counterspell dawdle a moment, and even then it was a simple "overpower the half-made wand and make it explode" since nobody knew how to counter a pocket dimension - nobody had known since the Days of Wonder - this was exactly the sort of lost lore she'd half hoped and half feared to meet --
Aeslin wasn't exactly surprised when the spell didn't fall apart, but the ley-lines fell away around her and all her sight turned black and silver as the spell took her.