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If the shambling corpse can't just push the door, Jack will look for a release/switch.

Mourkol rolls his incorporeal eyes at his master. Nothing on the other side. And I cannot see through the walls themselves...

The troll zombie 'William' presses on the door again but it does not budge.

Jack examines the newly revealed seam and notes three stone plugs designed to prevent the door from sliding open. Each of the three plugs glows with magical power to Gur's vision

Jack will try to remove them if he seems it safe. Unless the magical sighted people stop him.

After declaring the magical bolts, and since no one could detect traps, Ke'Sha just waits far from the door to see if it can be removed without dispeling magic.

Jack uses several methods to try to move the plugs but, like the security bars of a safe, they refuse to budge. It seems the Alteration magic is preventing them from moving

Allilhain steps closer and inspects the plugs. Well, they do seem to be Alteration magic. A dispel might logically work, but I used my only iteration prepared today on the green figures... Perhaps something simple and more specific... She quietly recites a simple phrase and taps on the door with her staff in a brief staccato; rap tap-tap-tap tap. A quiet cunk-cunk is heard as Jack sees the first two plugs slide out of the door and into the wall; leaving only one remaining bar. Satisfied she nods, I suppose that leabes just one to deal with. Jag, did you say earlier you also had this spell prepared?

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Allikhain casts Knock on the secret door. Two of the bars/plugs retract.

Ke'Sha nods appriciatively.

"Oh uh me. Yes indeed. I have one more prepared after this as well."
Jag will approach and cast it, then dodge to the side.

Jag duplicates Allikhain's Alteration and the final plug slides out of the way. He swiftly moves to one side. Against magical effects like this, our simple spells will only prevent it from sealing again for about 10 minutes or so. Once we open this we should leave it open, or place something to prevent it from closing completely again in order to keep our path clear.

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Jagrinder casts Knock on the secret door. The final bar/plug retracts

“Jack, do you still have those iron spikes? They might be able to block the door open.”

Ke'Sha peeks through the door from afar, sharing Gur's sight to detect magic, but waits for the others stepping through the door.

"Yeah I have a couple left."
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I'm assuming, for some reason I can't find Jack's sheet. Found it 3 spikes left.
I will put one here, that should stop it from fully closing."
He will put it in the jamb of the door on the unhinged side.