They cross the river, twice. Julio and Anton throw their packs across first, presumably to avoid damaging their spellbooks. The water reaches to Tencednil's chest at it's highest. Julio cleans everyone off.

The cavern splits into caves and crevices. At this point, nothing looks artificial. It's only five minutes in when Anton stops by an unremarkable wall in the middle of a long cave.

"I think this is it." He moves his hand across the wall, leaning against it. "Should be around here somewh—" His fingers pass through, six feet above them.

"Ah. Mika, help me up?"

Mika grabs Anton by the waist and lifts him. His body slowly vanishes into the wall without so much as a ripple.

"Alright, there's tunnels here! This must be it." His hands appear through the wall. "Julio, grab on, I'll lift you up."

Julio climbs up, looking uncomfortable the whole time.

"Want me to help you up?" He asks Tencednil.

She could use the help, and it doesn't sound like there's anything ambushing them up there.

"Please."

She'll still send the shadow ahead just in case, of course.

Her familiar flies ahead. Nothing comes through their empathic link.

Mika lifts her up and through the illusory wall. He climbs up after her.

The other side is a crossroads. The stone appears to be unworked, but Tencednil knows it wouldn't naturally form such a shape.

"The door supposedly looks indistinguishable from the rest of the walls. Julio, Tencednil, fan out and look with detect magic. We're looking for abjuration, but I doubt there's anything else here."

She's... not great... at identifying spell schools, but she can Detect just fine, and if she doesn't wait the ten seconds nobody will know.

Cantrip time it is!

About sixteen feet down the left hallway, part of the stone is magical! It is indeed otherwise indistinguishable from the rest of the stone, which flows like the walls of a natural cave.

The magic aura is around six feet high and three feet wide.

As soon as she gets an aura located, she ceases her focus on the cantrip. "Aura over here. This would be the Arcane Lock you were looking for?"

The others run over. "Indeed," Julio says, "this is abjuration. Mika, you're up."

Mika grunts, and pulls out a dagger and a small hammer. "This'll take a few minutes."

He holds his ear up to the door and starts tapping the stone in regular intervals with the tip of the dagger.

She lurks ominously over Julio's shoulder. The shadow will float in closer, to hopefully provide a quick warning if something goes wrong.

Over the next minute, Mika's tapping accelerates. If Tencednil listens very closely, she can hear the sound of the stone start to change subtly with each tap, before he suddenly pauses.

"Got 'er figured out, just a little bit longer." He goes slower this time, but very precise. After a couple more minutes, there's a sound of fire crackling and the wall shifts suddenly.

He puts away his tools and starts to push on the door. "Ughh... she's heavy."

The door opens into a small stone room, with a hide carpet on the floor. An old wooden desk and chair are in the corner to the party's left. Two open doorways are in the far corners of the room.

The stench of rotting flesh fills the air.

Julio covers his face and groans. "That's nasty. What—"

A zombie shambles out of the right corner door.

Groan...

Well, zombies aren't a great target for Color Spray. She signs <Up> to the shadow and takes aim for an Acid Splash, once things are clear enough for that to not be entirely hopeless.

...It doesn't know sign, does it. Hopefully it figured out not to be in front of the zombies in its own.

Her familiar flies up, of its own accord.

A second zombie comes out the same door. They lurch towards the party.

A beam of grey light emanates from Anton's finger and strikes the wall, missing the first zombie.