Giving the spine a bit of a shove to test it, Andrømeda takes a step back before raising a foot and slamming it into the side of the spine. (Not sure if strength or athletics, so I'll roll both, with advantage from bear totem)

STR: 18

Athletics: 24

(Since you're just trying to brute strength it, it would be STR in this case.)

With a mighty kick to the stone, Andrømeda topples it on her first try. Underneath where the stone once stood is a hole with a spiral staircase downward.

Waving a hand at the others, Andrømeda calls out, “Am found de door!”

Kwiz walks up and again appreciating that sometimes pure strength actually is the answer says “well done!” He then directs the floating text hovering near his head to float down and into the hole to show him what is here.

Kwiz's floating text of dim light and magic floats ethereally down the spiral staircase until it comes out at the bottom. This is what it sees.

Seeing through the invisible eyes for a moment, Kwiz directs it to explore East.

It explores east until it spots a room, into which it glides.

Inside it sees two sealed stone sarcophagi rest in alcoves dug into the south wall here.

We'll roll Perception to see whether or not it would notice it - low-ish DC of 10: 13 

You notice it.

Have it go through that hole then :)

The tunnel is narrow - only about 2' wide, if Kwiz had to guess. It's a good thing he's using a mostly incorporeal ball of magic to navigate these tunnels. In the room that the tunnel leads to, Kwiz sees the bones and rotting saddles of Lady Alagondar’s horse as well as two other horses.

As the spectral mind of his spellbook now starts to explore West of the stairs, Kwiz thinks back and tries to remember anything about Lady Alagonda ((history 11))

Kwiz doesn't remember anyone mentioning her, by name. Honestly, Kwiz might not have even known her name, but at the very least, you assume that she is the faked dragon slayer that was buried here whose sword you are looking for.

As your ball of magic leaves the room with the horses, you notice that the flooring seems to be a mixture of rotting wooden planks and packed dirt floors. You notice the same thing as you wander into the western hall. In this room, you see four sarcophagi set back into alcoves similarly to how the other two were set in the eastern room.

Glad he’s able to get a layout, though a bit disappointed in his history readings, Kwiz makes a mental note to look up Lady Alagonda the next time they get to a library, and sends the mind of his Awaked Spellbook North to see what lies in that direction.

He then explains what all he’s seen to the others waiting outside, ritually casts detect magic, and is ready to follow as they explore below. Though now he’ll be keeping an eye on the finer details of the burial mound looking for signs of traps, and or anything of historical significance ((investigation 25))

Finally, making your way all the way up north, you see the same mixture of rotten wood and packed dirt on the floor in the northern hallway leading into the room. In this room, there are two sarcophagi set into alcoves in the walls. The area north of the sarcophagi has the bones of a Huge dragon, embedded in its walls. The dragon’s skull rests on the floor.

So, what are the marching orders? Who is going first down the stairs?

(Kwiz told us all what he saw, no? So we know that there aren't any obvious enemies?)

 Andrømeda makes her way down the stairs first, lit torch in hand and moves to the South side of the bend so everybody could get down, saying to the rest of the group as they arrive, "Am think, if vi are cautious, vi could each check one of de rooms. Den's not too large, vi should be able to call for eachother if needed, ja?"

Though he’d like to check everywhere eventually, Kwiz first suggests they head north. He’s excited to see an actual dragon skull. Looking around as they walk he’s clearly excited to have found what appears to be an actual ancient burial mound of a dragon, and hopes the rumors of a magic sword are true.

((reminder of Investigation roll above, as well as having cast Detect Magic))

Quote from DifferentNoodle >>

(Kwiz told us all what he saw, no? So we know that there aren't any obvious enemies?)

 Andrømeda makes her way down the stairs first, lit torch in hand and moves to the South side of the bend so everybody could get down, saying to the rest of the group as they arrive, "Am think, if vi are cautious, vi could each check one of de rooms. Den's not too large, vi should be able to call for eachother if needed, ja?"

As soon as Andrømeda gets to the bottom of the stairs, she sees 3 purple-ish glowing wisps light up and then fly away. One goes north, one goes south, one goes around the center column to the west.

((I haven't forgotten the investigation roll, either. I'll apply it to the first opportunity Kwiz will have to use it as we step through this. Since Andrømeda went down first, I need to know what she's doing first.))

Andrømeda nods, not too bothered either way about which way they go, and begins to make her way around the central pillar and towards the Northern room, keeping her torch raised and a wary eye for anything dangerous.

Perception: 12