The Sunken Fortress of Valdris: Race for the Relic
The Sunken Fortress of Valdris: Race for the Relic
The party descends into the partially submerged ruins of Valdris, a fortress swallowed by the earth centuries ago, to retrieve the Heartstone of Valdris — an ancient relic of immense power — before the Iron Veil, a ruthless mercenary cult, claims it for their shadowy patron. Every flooded corridor and collapsed hall hides both deadly guardians and rival agents closing in. Time, water, and steel stand between the adventurers and victory.
Read Aloud
You stand at the lip of a vast sinkhole where the earth has simply surrendered, swallowing the outer walls of Fortress Valdris whole. The stench of stagnant water and wet stone rises from below like a cold exhale. Stone battlements jut from the muddy walls of the pit at broken angles, draped in pale fungal growths that pulse faintly with bioluminescence. Iron torch-brackets still line the descending staircase carved into the sinkhole's edge, their rusted arms empty — but someone has left fresh boot-prints in the mud, leading down into the dark.
Description
The party arrives at the entrance to the sunken fortress. The outer gatehouse has collapsed inward, leaving a treacherous descent of crumbling stairs and rope-bridge remnants into the upper level of the fortress below. The fresh boot-prints belong to an Iron Veil scouting party that arrived roughly one hour ahead of the players. A DC 12 Wisdom (Survival) check confirms the tracks: at least six humanoid creatures, one dragging something heavy (a battering ram for interior doors). A DC 14 Intelligence (History) check reveals that Valdris was a fortress-monastery of the Order of the Silver Flame, sealed when a catastrophic tremor caused it to sink — the relic was never retrieved because the lower vaults flooded immediately.
DM Notes
Encourage the party to assess the situation before descending. DC 13 Wisdom (Perception) to spot a rope left by the Iron Veil dangling over the eastern edge — using it grants advantage on the descent check. The descent itself requires a DC 11 Dexterity (Acrobatics) or Strength (Athletics) check; failure means the character slips and takes 5 (1d10) bludgeoning damage and arrives at the bottom prone. Let the Rogue attempt to read the tracks with Thieves' Cant carvings left in the stone — a DC 12 Intelligence check reveals an Iron Veil symbol meaning "Secured — proceed."
Read Aloud
The great hall of Valdris opens before you like the ribcage of a drowned giant. Columns of black granite rise from knee-deep floodwater that stretches the length of the room, its surface perfectly still and dark as ink. Tattered battle-standards hang from the vaulted ceiling, their colors bled away to grey, and the silver-inlaid crests of the Order of the Silver Flame still gleam faintly on the archways. Near the far end, an iron portcullis has been freshly torn from its moorings — bent bars discarded in the water — and a slick of torchlight flickers beyond it, moving away.
Description
The flooded great hall serves as the primary navigation challenge of the session. The water is 2 feet deep across most of the hall, reducing movement speed by 5 feet. Hidden beneath the surface are collapsed pews, broken statuary, and scattered bones of the fortress's original garrison. At the center of the hall, around the base of the largest column, a nest of Swarms of Quippers lurks — disturbing the water carelessly will draw them out. The Iron Veil has already passed through and damaged the portcullis ahead, meaning the party can follow without forcing it themselves. A DC 15 Wisdom (Perception) check while wading reveals a glint below the water: a silver holy symbol of the Order (worth 25 gp) and, more importantly, a partially submerged iron key on a skeleton's wrist.
DM Notes
The key unlocks the reliquary door in Scene 5, bypassing a mechanical trap. If players move recklessly — running, making large splashes, or using fire spells near the water — trigger the Quipper Swarm encounter (see Encounters). A DC 13 Intelligence (Nature) or Wisdom (Perception) check while examining the water surface warns of movement beneath. Reward cautious, creative navigation: the Wizard's Mage Hand, the Cleric's Guidance, or the Rogue's careful stepping (DC 12 Dexterity — Stealth) can all allow safe passage. The moving torchlight beyond the portcullis is Iron Veil soldiers — if the party hurries, they can catch up before Scene 4.
Read Aloud
A vaulted corridor stretches ahead, its stone floor cracked and heaved by centuries of pressure. Three oil lanterns have been spiked into the mortar between stones, casting harsh amber light over a squad of armored mercenaries who snap to attention the moment they hear you. Their tabards bear a symbol of a downward-facing iron gauntlet clutching a blindfold — the mark of the Iron Veil. The foremost among them, a scarred woman in a visored helm, draws a hand crossbow and levels it at you with the cool efficiency of someone who has done this many times before. "The Veil doesn't share," she says flatly. "Turn back, or we leave you here with the stones."
Description
The party intercepts an Iron Veil rearguard — four mercenary soldiers left to slow down any pursuers while the main force, led by Commander Sable Drenn, pushes toward the reliquary. The scarred leader is Sergeant Harwick Mole, a grizzled mercenary who prefers intimidation over combat but will fight ruthlessly if cornered. This scene has a dual nature: it can resolve as combat or as a social encounter. The soldiers are loyal to coin, not cause — Sergeant Mole can be persuaded, deceived, or intimidated. The corridor is lit only by their lanterns; if they are doused, the Iron Veil soldiers fight at disadvantage (they have no darkvision) while most of the party likely does.
DM Notes
Social resolution DCs: DC 14 Charisma (Intimidation) to make Mole stand down and let the party pass — he respects power. DC 16 Charisma (Persuasion) with an offer of gold (at least 50 gp per soldier) to bribe them — Mole mutters "Commander Drenn's not paying us enough for this anyway." DC 13 Charisma (Deception) claiming to be Iron Veil reinforcements works only if someone has a stolen Iron Veil tabard (possible to find on a body in Scene 2 if players searched). Combat resolution uses the Rearguard encounter stats. If combat breaks out, Mole retreats after dropping to half HP and warns Commander Drenn — increasing urgency in Scene 5. Mole won't reveal Drenn's plans voluntarily but slips up if the party passes a DC 13 Wisdom (Insight) check during negotiation, revealing he is nervous about "what's sleeping in the lower vault."
Read Aloud
The corridor opens into a circular antechamber whose walls are lined floor-to-ceiling with carved stone faces — dozens of them, each different, eyes closed in solemn repose. At the room's center stands a stone plinth bearing an inscription in old Elvish script, its edges worn smooth by centuries of reverent hands. Then, one by one, the stone eyelids scrape open. The carved faces turn toward you in unison, their hollow eyes tracking your every movement with a grinding sound like millstones. A low, resonant hum fills the air — and two of the armored figures flanking the plinth step forward with a rattle of ancient joints, their visored helms empty of any living face.
Description
This is the guardian antechamber of the reliquary, protected by animated armor constructs left by the Order of the Silver Flame. The stone faces on the walls are a detection array — a magical alarm system that animates the armor guardians when intruders enter without speaking the passphrase. The passphrase is inscribed on the plinth in old Elvish: "We walk in silver flame, not shadow." A DC 14 Intelligence (Arcana) check identifies the plinth as a guardian-trigger; a DC 13 Intelligence (History or Religion) check lets a character recall the Order's traditional greeting. Speaking the phrase aloud in Elvish causes the faces to close their eyes and the armor to stand down. The Iron Veil already blundered through here — one of the animated armors has been damaged (reduced to 18 HP) by their passage.
DM Notes
Reward players who speak Elvish or who thought to research the Order before the session. The Wizard almost certainly knows Elvish. If the party fights, use the Animated Armor encounter card — one armor is already damaged at 18 HP. The faces on the walls cannot be attacked or destroyed by conventional means; spells like Dispel Magic (DC 13) can suppress one face's tracking for 1 minute. Players who attempt to sneak past the plinth without reading it must beat a DC 15 Dexterity (Stealth) group check — failure triggers the guardians. A Cleric who presents a holy symbol of a lawful good deity gets advantage on the Persuasion check equivalent (DC 12 Religion) to attempt to "reason" with the magical constructs by appealing to their divine purpose.
Read Aloud
The reliquary is a vaulted chamber of breathtaking craftsmanship — even in ruin. Mosaic floors of blue and silver tile depict the history of Fortress Valdris beneath a thin sheen of flood-water seeping through the far wall. At the room's altar-end, set into a niche of polished obsidian, the Heartstone of Valdris pulses with a slow, warm amber light — a fist-sized gem threaded with veins of living gold that beat like a heart. Standing before it, her gauntleted hand already reaching, is a tall woman in black plate armor etched with iron filigree. She turns at your approach, and her expression is not surprise — it is calculation. "Ah," says Commander Sable Drenn. "You are faster than I was told. That is inconvenient."
Description
The climactic confrontation. Commander Sable Drenn and her two remaining elite Iron Veil agents (Spies) stand between the party and the Heartstone of Valdris. Drenn is a pragmatic, coldly intelligent villain — she wants the Heartstone not for glory but because her patron, a faceless figure known only as the Architect, has promised to use it to unseal a collapsed planar rift beneath the fortress. If the party retrieved the iron key from Scene 2, they can grab the Heartstone from its locked niche as a bonus action, denying Drenn the chance to seize it during combat. Without the key, a DC 15 Strength (Athletics) or DC 16 Dexterity (Thieves' Tools) check is needed to force or pick the lock while under pressure. Drenn will bargain briefly if brought below half HP — she is survivalist above all — but she will never simply surrender the Heartstone without a fight.
DM Notes
This scene is the emotional and mechanical climax. Start with a brief role-play exchange — Drenn is menacing but articulate. She reveals that she knows who sent the party and implies their patron may not be entirely trustworthy either (plant seeds of future intrigue). Combat uses the Commander Sable Drenn encounter card. Dynamic terrain: the seeping far wall can be broken open with 15 damage to flood the chamber over 3 rounds, creating difficult terrain but potentially forcing Drenn's armored agents to their knees. If the Heartstone is touched without the key ritual, it deals 2d6 radiant damage to creatures of ill intent (Drenn and agents automatically fail; party members must pass a DC 13 Wisdom saving throw or take damage — a moral test). Award the session's full XP and treasure whether Drenn is defeated, bargained off, or flees.
Monsters
Tactics
The three swarms attack in unison, converging on the creature with the lowest current HP (Blood Frenzy gives them advantage against any wounded creature). They stay submerged as long as possible, attacking from below the waterline and surfacing only to strike — targets cannot see them coming without a DC 14 Wisdom (Perception) check. Two swarms focus a single target while the third intercepts any creature moving toward the exit. They scatter (disengage and flee) if reduced below 7 HP individually, but reform if the party lingers in the water for more than 2 rounds after dispersal.
Terrain
Flooded great hall with 2 feet of standing water covering the entire room (difficult terrain, -5 ft movement). Submerged pews and rubble make the terrain unpredictable — any creature that Dashes must succeed on a DC 12 Dexterity saving throw or fall prone. Columns of black granite provide cover above the waterline but not below. Fire-based spells cast at the water's surface have no effect on submerged swarms but create a spectacular visual distraction (DC 12 Wisdom saving throw for swarms or they lose their next attack due to disorientation — DM discretion).
Monsters
Tactics
Sergeant Harwick Mole commands his soldiers with military discipline. He opens by directing two Spies to flank the most armored party member (the Fighter), exploiting Sneak Attack, while he engages with his Longsword — he knows that keeping a melee fighter busy limits the party's action economy. The third Spy hangs back with a hand crossbow, targeting the Wizard or Cleric from cover behind a collapsed doorframe. Harwick himself uses his heavy health pool as a buffer, staying in front to protect the ranged attacker. If Harwick drops to 29 HP or fewer, he calls for a parley on his next turn rather than fighting to the death, shouting "Hold — let's talk coin!" The Spies defer to Harwick; if he falls or flees, they lose morale and one immediately attempts to escape.
Terrain
A vaulted stone corridor 10 feet wide and 40 feet long, lit by three spiked oil lanterns. A collapsed door frame at the far end provides three-quarters cover (+5 AC) for anyone crouching behind it. Dousing all three lanterns (as an action per lantern, or one Darkness spell) plunges the corridor into complete darkness — the Iron Veil soldiers have no darkvision, putting them at severe disadvantage. The floor is dry but cracked and uneven; moving at full speed requires a DC 10 Dexterity check or the creature's next attack is made with disadvantage due to stumbling.
Monsters
Tactics
The two Animated Armors move in tandem, protecting the central plinth. One advances on melee combatants while the second circles to flank, using the columns for cover between moves. They are relentless and fearless — immune to charm, fright, and morale — and will not pursue enemies beyond the antechamber's archway (they are bound to guard this room only). The damaged armor (18 HP, already struck by the Iron Veil) has a cracked left pauldron that causes it to attack at disadvantage with its left arm; a DC 13 Wisdom (Perception) check during combat reveals this weak point, granting advantage on attacks targeting that side. Antimagic Susceptibility: the Wizard's Dispel Magic or any antimagic effect immediately incapacitates one armor while maintained. The armors stop attacking the instant the passphrase is spoken aloud in Elvish, standing down with an air of grinding finality.
Terrain
A circular antechamber 30 feet in diameter, with carved stone faces covering every wall from floor to ceiling. The faces track all movement — creatures cannot Hide in this room (the faces silently relay positions to the armors). A stone plinth stands at the center; using it as cover requires squeezing (disadvantage on attack rolls). Two stone archways lead in and out; the armors block the forward archway, creating a natural chokepoint. The floor is dry mosaic tile, beautiful but slippery where ancient grout has worn away — DC 11 Dexterity saving throw when a creature is shoved or knocked back, or fall prone.
Monsters
Tactics
Drenn opens combat with her Leadership ability (if Recharge permits), granting her two Elite Agents advantage on their first attacks. The Agents immediately attempt Sneak Attacks on the Rogue or Wizard — priority targets with lower HP. Drenn herself advances on the Fighter, using Parry to mitigate incoming damage while making measured Longsword strikes. She is never reckless — she uses the altar for cover if pushed back and calls retreats to better positions. If brought to 26 HP or fewer, she drops her sword point to the ground and initiates a terse parley, offering to let the party leave with the Heartstone in exchange for them never revealing what they saw here. This is a genuine offer — she wants to survive and report to the Architect. If the party refuses, she fights to 0 HP before admitting defeat. Agents fight until Drenn concedes or falls, then immediately surrender.
Terrain
The reliquary is a 40 by 50 foot vaulted chamber. The obsidian niche holding the Heartstone is at the far end on a raised dais (5 ft. high, costs 5 ft. extra movement to ascend). Water seeps through cracks in the far wall — each round of combat, the seeping worsens: after Round 3, the floor is difficult terrain (2 inches of water, no speed penalty). The far wall can be destroyed (AC 11, 15 HP) to flood the room faster, creating 2 feet of water by Round 6 and imposing the full difficult terrain penalty. Mosaic pillars provide half cover (+2 AC) for anyone positioned behind them. The Heartstone radiates dim amber light in a 20-foot radius.
The ancient relic of the Order of the Silver Flame — a fist-sized amber gemstone threaded with veins of living gold that pulse like a heartbeat. It functions as a Holy Symbol for any Cleric or Paladin who attuned to it, granting +1 to spell save DC and the ability to cast Beacon of Hope once per day without expending a spell slot. It is the primary objective of the session and likely the MacGuffin of a larger campaign arc.
A small, iron-bound journal found in Commander Sable Drenn's satchel, written in a coded Iron Veil cipher. A DC 16 Intelligence check or a week of study reveals it contains coordinates for three other sites the Architect has marked for investigation, as well as a partial description of the Architect himself: 'tall, left-handed, smells of pine resin and ozone, never removes the silver mask.' Excellent future campaign hook.
The combined operational funds of the Iron Veil's Valdris expedition — a leather purse containing 140 gp and 60 sp.
Recovered from the skeleton in the Drowned Hall. A masterwork piece of pre-collapse craftsmanship, still potent as a holy symbol. A Cleric who uses it as their holy symbol finds that undead within 10 feet make their Turning saving throws with disadvantage while it is held aloft.
Found in a waterproof case tucked into the Iron Veil's supply satchel — they brought it for the expected flooding but never needed it. Allows the drinker to breathe underwater for 1 hour.
Story Hooks
The Cipher Journal points toward the Architect's next three targets — the party can race to secure these sites before the Iron Veil regroups. The Heartstone of Valdris may require delivery to a specific patron, institution, or scholar, raising immediate questions about who actually sent the party and whether the Echo of Warden Aldric's anguished warnings about the relic's true nature were a warning they should have heeded. Commander Sable Drenn, if she survived and escaped, will not forgive this defeat — and she now knows the party's faces.
Conclusion
Wrap Up
With the Heartstone of Valdris in hand and the Iron Veil's expedition broken, the party ascends the crumbling staircase of the sinkhole as the fortress groans beneath them — the flooding has accelerated now, and Valdris will be fully submerged within the hour, erasing whatever secrets remain. The Echo of Warden Aldric appears one final time at the threshold: he watches the Heartstone leave the fortress with an expression caught between relief and unease. He opens his mouth as though to speak a warning — and dissolves into silver light before a single word escapes him.
Cliffhanger
As the party emerges into open air, a figure is waiting at the edge of the sinkhole. Cloaked in grey and standing utterly still, they are tall and left-handed — one hand resting on the pommel of a thin blade — and a silver mask covers their face from brow to chin. They look at the Heartstone, then at the party, and speak in a voice of quiet authority: "I see the Iron Veil failed. No matter. I believe you have something of mine." They take one unhurried step forward.
Next Session Hooks
- The Architect has arrived personally — who is behind the silver mask, and what is their true claim to the Heartstone of Valdris? The party must decide in moments whether to fight, flee, or negotiate with someone who may be the most dangerous person they have ever encountered.
- The Iron Veil Cipher Journal's three coordinates lead to a collapsed aqueduct, an island lighthouse, and a sealed noble crypt — each likely holds another relic or piece of intelligence the Architect is hunting. The race is back on.
- The Echo of Warden Aldric's unfinished warning nags at the Cleric in their dreams that night — a vision of the Heartstone not as a beacon, but as a key fitting into a lock the size of a mountain. Something is on the other side of that lock, and it is very, very awake.
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