Depths of the Broken Seal

You drop in from the northern entrance in Roots of Underkeep and arrive near the top of the cave (20,8). It's a small level with one job: reach the obelisk that sank below the earth and copy its runes for Khelebar. Expect Veinbiters (17,15) – those beetles are what undermined the stone in the first place.

In the south of the level there's a grid of nine lights (7,20) and a sign beside it: "Four points seek one heart. Let their paths meet in the center." (10,19). Buttons on the west side shift the light in each row, buttons on the north side shift it in each column. Set the X pattern – four corners and the centre – and the door to the north opens. If you lose track, move one row or column at a time and check what changed after each press.

The same panel opens an optional side route. The T pattern – the top row, the centre and the bottom middle light – slides back the secret walls in the west (4,18), and they stay open only while the T is showing. Behind them is a chest with Frostbite Edge and an Emerald (2,18). Switch back to the X pattern when you want the main route.

Veinbiters hold the northern part. The locked chest up there (18,13) needs Lockpick Tools and holds a Potion of Resurrection, the Recipe: Potion of Cure Poison, a Potion of Poison and random loot.

The broken north-western obelisk lies sunk below ground level (10,7). Walk up to it and copy the runes; that's the fourth set for Khelebar, so you can head back to the village for the teleportation stone. The broken stone is also what the druid in Roots of Underkeep wants reported for his quest The Fallen Stone.

Reaching the obelisk also slides back further secret walls nearby (15,7), so check where the new passage joins up – it may shorten your way out. Deeper progress in the cave on the route to the fourth obelisk calls for the reinforced pickaxe from the dwarven trader; whether that hard rubble is in this level, we can't confirm.