Underkeep Tower

The gate of Underkeep Tower only opens with four Runic Segment keys. The first is in the chest in the Source chambers under the cemetery once you have made your decision about the Source, the second on the altar in Mireheart past The Thing, the third on the ground beside two coffins in the Dragon's Lair once the dragon has been driven off, and the fourth you buy from Torren on the road to the tower for 300 gold, once you hold all the obelisk scrolls for Khelebar. An adventurer called Torin also turns up near the tower selling a Key Fragment for 300 Gold; whether that is the same person and the same item is not confirmed, so don't swap the names around. The three Golden Keys from the High Clerics belong to the Source Gate, not here.

Before you slot the keys in, stock up on supplies and brewed potions for a long stay – whether you can get back to the village from inside we cannot confirm. Collect Soulcleaver from Durok as well.

The first floor has two pressure-plate rooms and the same rule in both: step on every plate exactly once and the gate opens. Stand on one twice and you have to walk back to the start and use the reset switch. We cannot confirm the tile-by-tile route, so plan the whole walk before your first step.

Between the plate rooms you meet a shadow enemy that shrugs off your attacks. Open the curtains at the windows to let light in – only then is it vulnerable. Kill it and carry on to the second plate room.

The second floor runs on coffins that move you into a mirrored version of the rooms. Use the first coffin and clear the enemies in the mirrored area. Light both braziers at the sides of the gate, beat the enemies behind it and use the coffin inside. Back in a different part of the floor, press only the two outer wall switches and leave the middle one alone. Then use the coffin there and return to the first one. That opens the way east to the room with three knight statues.

In the statue room, use the coffin, defeat the enemies on the other side and note where the statues stand over there. Come back by coffin and arrange the knight statues to match. We cannot confirm the exact positions, so read them off on the spot. Get it right and the route to the third floor opens.

Take the inscription about the gallery literally. Following the painting, stand all four statues along the back wall: wizards in the corners, warriors beside them. The middle painting on the back wall then disappears and uncovers a passage. We cannot confirm the exact tiles, so compare the statues with the painting.

The small room with the inscription about a dark room looks like a dead end. Close the entrance door with the switch inside, and once it's dark in there, look along the left-hand wall for another inconspicuous button. Press it; it only works while the entrance door is shut.

On the fourth floor, read the runes on the main doors first – two are blue and two orange. Then use the blue teleport to visit the rune rooms one by one, and in each one switch on the colour matching that same rune on the doors, leaving the other colour off. Keep teleporting until you're back in the hall. The right setting opens the main gate. We cannot confirm which colour belongs to which symbol, so always read your template off the doors.

An optional detour sits beside the main gate: for the second doors, switch on only the single rune marked on them in the rune rooms, and take the chest behind. You don't need it for the main route. In the last room of the floor a wall blocks the way on. Stand with your back to it and reverse into it – you pass straight through.

The Archmage starts with five shields and most of his attacks hit the whole party. Against the shields try attacks that deal damage several times, and keep the back row healed too; against mostly magical damage an elemental resistance potion is worth drinking. There are resurrection shrines at the entrance to his chambers, so keep gold for revives or carry resurrection items.

With the Archmage down, go back to the first floor and use the newly opened passage into the underground; we have not confirmed whether this passage requires Durok's Soulforge weapon to have been collected before entering the tower. Torren waits below, summoning demons from a red portal. Pull the party back to the rear wall and thin out the demons first, then hit him and the rest with area attacks, and once he's alone focus everything on him. Demons keep arriving, so treat the rear wall as a way to delay them, not as safety. Beating Torren leads into the closing scene and the credits.