"Let's get moving. Do we want to try and make our way to the shrine upstairs first?"

I think so - but let us pass through the entryway - I am wondering how much of our actions in the real world affect this conjured one. Could the shrine be in the entrance hall corner because we moved it there? As well, if this is more a back in time thing as you theorized, we may have to find the actual stairs to go upstairs. We never saw evidence of one but I picture a grand stairway somewhere. 

Another thing I wonder - is Lady Redmane (or her ghost) in here too? Are the servants the diary mentioned here? I am not looking forward with overwhelming enthusiasm.

Therne will report the overwhelming presence of conjuration magic, then, but still suggest looking for the casket. She's going to try and keep a lookout for any place where the magic seems particularly strong, or weak, or not there at all.

[OoC]: What's the plan? Are you moving onward?

[ooc assuming we get the same room description as Abner did? The south door that would lead towards the study and game room is the black void? Is the west door to the dining room ok?]

Quote from skuk >>

[ooc assuming we get the same room description as Abner did? The south door that would lead towards the study and game room is the black void? Is the west door to the dining room ok?]

[OoC]: Yes to all questions.

After a search of the kitchen for clues, portals, scraps of reality (investigation 16)

Master Abner, could you put a Light on Brother Brozak's shield, so he can lead the way as he so capably prefers? Or some other portable item if its better. And can we head through the dining to find our way to the shrine either where we left it or where we found it? I assume none of us prefers that void-door yonder

[OoC]: Checks relying on sight have disadvantage in the dim light. Red's second roll: 15

Red's search of the kitchen yields few results. As far as he can tell, the southern door is as impassable as a pitch black wall of stone. The kitchen itself appears to be in good condition, with no signs of the disrepair from before. The items in the kitchen are tangible, suggesting that you are under no illusions.

 Therne is going to move the hand that's holding the flame up to the southern door -- just short of touching it, but looking to see if any light makes it through, or if the magic has any other effect. Is the darkness on the doorway or the wispy smoke giving off any signature different from the conjuration that the house is giving off?

Investigation: 18 (You said Wisdom/Perception checks had disadvantage. But, second roll:) 13

Quote from pocketmouse >>

 Therne is going to move the hand that's holding the flame up to the southern door -- just short of touching it, but looking to see if any light makes it through, or if the magic has any other effect. Is the darkness on the doorway or the wispy smoke giving off any signature different from the conjuration that the house is giving off?

Investigation: 14 (You said Wisdom/Perception checks had disadvantage. But, second roll:) 8

[OoC]: I'm assuming you've cast the spell produce flame here? Also yes, Perception checks that rely on sight and any other checks that are obviously based on vision. Investigation in this case is included.

The doorway is completely opaque and does not react at all to the fire. Everything around you gives off an overwhelming aura of conjuration. The only other source of magic you can detect is a faint wisp of enchantment magic as you pass closer to the western door.

OOC: Yes, produce flame, and I'm assuming it's diminished in the same way that light is.

"Something here over here is different," Therne exclaims. "Something over here has a different magical signature, enchantment-based." She goes over to the door. She squints. "It's so hard to see in here. Could I perhaps get a little help from you, Adri? Or Red?"

Adri walks over and lights a torch.

"Do you think its the door itself or something behind it?"

Adri inspects the door for any magical properties. 

There isn't anything obvious about the door that appears remarkable. All objects, walls, ceilings and floors of the manor appear to have this shadow-like quality to them - as though reality itself has undergone a change.

OOC: But getting up close there's no better sign as to what's giving off the enchantment signature? With Adri helping can I roll with advantage?

[OoC]: Sorry if I didn't make it obvious, but it appears that the signature is coming from somewhere on the other side of the door, so you cannot see it currently.

OOC: Oh, OK, I was thinking maybe it was a small feature of the door, like a hidden mechanism. Gotcha.

"It must be on the other side." She looks at the others. "I don't like being led like this, but since we can't go back, I don't suppose we have much of a choice."

I have a theory, though it doesn't help us much - maybe the world we are in only shows us what the mirror has seen? If it was carried to the cellar through this door it might not have any knowledge of that one it has left blank.

[ooc I think we are just waiting for Broz and Ab to agree to go through to the dining room? it is the only door we got

while we wait - in the real house the windows were opaque with smoke and soot - how about the windows here? can we see out at all?]

The windows here are see-through, but show nothing beyond except an endless black void in all directions. You only even realise that the glass is transparent because you can see the edges of the frame through the panes.

Abner

Abner peels himself up off the floor, and nods with somber appreciation to Adri for the blanket. He casts Light on Brozak's shield, as suggested.

(Has anyone opened the western door yet?) "Looks like we ought to... open the door?"

"Let us go.  This place makes me really want to hit something."