Stepping into the chamber, Robin casts detect magic as a ritual, wishing to see if anything in hebre is magical.

(This would also end the polymorph on that air elemental thing in the previous chamber.)

Robin can make what looks like abujurtion magic emitting weakly from the belly of the corpse. The door to the cell is heavily rusted and locked. 

Moving to the cell door, Robin pulls out her thieve's tools and starts working to pick the lock...

Thieve's tool check: 11 Guidance: 1

It takes a few seconds as Robins works on the lock with the tools until everyone relizes her turning of the picks wasn't moving the bolts at all and is more scraping rust off the locker tthan moving the locked up internals. 

Onyx still seems a bit distracted by watching every shadow or possible hiding  spot. Seeing Robin struggling, he offers:“should i give it a shot? I picked up a trick or two over the last week and i wouldn’t mind trying them. I would just need to borrow your tools for a moment…”

After a momen working with the tools, Onyx returns them slight bent from the poor attempts and short of several small tumblers falling out of the keyhole. (No more attempt at picking the lock is possibe)

Salys sends Bearskr to try and break the lock, casting guidance to increase its odds.

Bearskr Athletics + Guidance: 18+3

Bearskr jogs to the the door and takes a moment as it turns it's head to the horizontal before it grabs down on the door and starts pulling harder and harder. At start nothing happens before wiuth a few yanks, the door starts to bend and buckle until the hinges gives on the door. Carefully venturing into the cell and turning over the body, it's in a similar state of decay, a bit of search uncovers a spellbook in perfect conidtion on the corpse.

Sorting through the pages, looks like a wizard spell but not a high level ones but on the last page, instead of the formula for a spell is a chart with several missing slots.

Spells within the Book:

Level 1

Alarm, Burning Hands, Charm Person, Chromatic Orb, Color Spray, Comprehend Languages

Level 2
Alter Self, Arcane Lock, Blindness / Deafness, Blur

SECRET DOOR WHERE?

Robin picks up the spellbook and pages through it. She will hold up the last page for the others to have a look at. Is this the item that detected as magical?

Yes, it's an enduring spellbook

Exposed Map:

Salys looks over the map, "Think its about this place? Has anyone seen any murals?"

DM note: There was a giant Giant mural everyone  saw in hallway leading to the stairs going down. (Marked as Giant on the map)

"Yep, giant mural out by the stairs." Robin nods towards the door. She sticks the book in her pack and then turns back towards the hall. "Shall we check out that othre hall on this level, before looking to the stairs?" She exits the prison and nods to where the hall turns.

Resfaen follows along behind Robin, waiting for the next attack to come.

Looking around the corner of the hallways, Robin finds another set of stairs but these lead up. 

"Seems we have a choice then." Robin says with a frown at the new set of stairs. "Do we want to head up or down?" She glances to the group. "I'd vote for up, as the 'brains' of this thing are likely in that direction."

“I think the elemental part may be the air creature we saw behind the door. Anyone of you saw a magic item?” Onyx adds to the discussion while following.

[OOC: did Resfaen grab the armor and weapon that was in the Air elemental room? Or did the elemental wear that and is now part of the creature it was polymorphed into?]

It was transformed with the air elemental as per Polymorph wording.