Marginalia And The Old Mines

From the Grand Hall of Kaer Morhen, head to the southeast tower and spiral staircase, with the massive stone pillar in the center, and more steps leading down. Ignore all the stairs and instead inspect an old chest in the middle of the three archway alcoves. It contains an interesting book which you should immediately read in your Inventory menu. There is an odd margin note regarding the breaking of an illusion, and the key being this book. Apparently, all shall be revealed in the mines nearby.

Pass the dilapidated lake structures and the signpost for the Old Mines, following the track into the gully heading southwest. Sunken into the ground ahead of you is the old iron mine entrance itself.

Follow the tunnel into the first cavern, where your inspection of a rough-hewn pedestal is interrupted by a lumbering earth elemental. Face this burdensome sentry, and once it succumbs to your blade, move back to the pedestal and examine it to place the book you found on this plinth. Candles flicker to life, and a section of cave wall rumbles open. Continue west.

End: Stand Down! This Place Belongs to Radmir!

You explore a forge that is humming with magic. Go to the raised area with the fireplace, blacksmith bellows, and anvil. It seems the Eye of Nehaleni is picking up an illusion in this area. Interact with the bellows, and the fire speaks to you, warning you this place belongs to Radmir of Tor Carnedd. Reply how you wish, but mention to the soul of the fire that you wish to look around. This doesn’t sit well with the Ifrit, and it stands up, blasting you across the chamber. Face the Ifrit in monstrous combat.

Snuff the ifrit out, then approach the unlit hearth. The Eye of Nehaleni slowly reveals a secret compartment behind an illusion of a wall. Behind this are three chests containing some immense valuables! Gather them as this quest concludes.