Adventure Summary: A one-session underwater horror heist for four to five 7th-level characters. A salvage bell reaches the dry wing of a manor beneath Hollowmere Reservoir. The party must steal the original flood charter, free a trapped heir, and escape before the Drowned Curator seals the house inside its own memories.
Hollowmere Lantern Saga: Part 3 of 4. This adventure stands alone. Previously: The Drowned Road to Saint Orra. The saga continues with The Last Vigil of Hollowmere.
Overview
The Breathglass medallion or an independent survey reveals Hale House, the estate whose owners financed Hollowmere’s dam. One room remains miraculously dry. From that window, Orris Hale signals every night with a candle, though records say he died forty years ago at age nine.
Salvage engineer Ilyra Fen can lower the party in a brass diving bell. Inside, the Drowned Curator maintains a perfect archive of official lies. The original flood charter names the people who ordered the disaster and contains the valve sequence needed to stop the reservoir from overtopping during the coming vigil.
Background
Lord Bren Hale signed the flood order, then hid his son Orris inside an experimental air vault when the valley drowned. The vault’s preservation engine trapped Orris outside time and animated the estate archivist as the Drowned Curator. For decades, the Curator has edited portraits and ledgers so the Hales appear blameless.
Standalone hook: Ilyra offers 1,000 gp for the flood charter and Orris’s rescue. Saga hook: Ysabet’s medallion opens the diving bell dock and the prior reward supplies breathable air. Without either, Ilyra provides six pressure flasks and a copied service key, so no previous chapter is required.
Characters
- Ilyra Fen: A blunt salvage engineer who treats every dive as a sequence of solvable failures. She remains at the bell and manages the return cable.
- Orris Hale: A frightened but perceptive child preserved in the Air Pocket. He knows the manor’s speaking tubes and refuses to leave without his nurse’s ledger.
- The Drowned Curator: The archivist’s duty twisted into censorship. It values an orderly record above every life in the house.
- Lady Hale’s Portrait: A painted hunger that bargains for memories and knows the shortcut to the Archive Vault.
Setting
Hale House lies sixty feet below the reservoir. The Diving Bell Dock, Servants’ Gallery, Portrait Hall, Nursery, Air Pocket, Archive Vault, Mourning Chapel, and Heart Cistern form a flooded dungeon of sealed doors and trapped air.
Track four Pressure marks. Add one after a major failure, loud structural damage, or ten minutes spent outside an air pocket. At each mark, lamps dim and a corridor floods. At four marks, the Heart Cistern begins half full and the return cable jams, but the party always retains a difficult escape route.
Plot Outline
The party descends by diving bell, chooses a flooded or service route, crosses the Portrait Hall, rescues Orris from the Air Pocket, steals the true charter from the Archive Vault, and operates the Heart Cistern valves while fighting the Curator. Opening the house, defeating the Curator, or replacing its false master index resolves the dive.
1. The Diving Bell Dock
Ilyra explains three safety rules: keep one hand on a guide line, never open two pressure doors together, and answer no portrait with a personal memory. The descent requires two DC 14 Athletics, Arcana, or tinker’s tools successes. A failure adds Pressure and cracks one of six emergency air flasks, but the bell lands safely.
2. Servants’ Gallery
Silt Servants repeat their final chores and ignore anyone carrying a tray or wearing a servant’s ribbon. The party can cross with a DC 15 group Deception or Stealth check, repair the speaking tube to issue a false order, or fight. A defeated servant releases a memory bubble showing the route to Orris.
3. Portrait Hall
Six paintings ask questions about the visitors’ past. Each honest answer opens one door but gives Lady Hale’s Portrait a stolen memory token. Three DC 15 Insight, Investigation, or painter’s supplies successes reveal the frames can be rotated to make the portraits question one another. Failure adds Pressure but still opens the nursery.
4. The Air Pocket
Orris lives in a furnished cavern connected to the nursery by a speaking tube. He initially believes the party are Curator projections. Showing a modern object, naming Sister Ysabet, or succeeding on DC 14 Persuasion earns his trust. He gives the party the master index and reveals that three brass valves can release the house.
5. The Archive Vault
The true charter sits among five convincing copies. Clues from the ledger, portraits, and Orris identify it through three DC 15 Investigation, History, or forgery kit successes. Taking a false copy animates two Portrait Hungers. Taking the true charter causes the Curator to lock every pressure door and announce a correction.
6. The Mourning Chapel
Orris’s nurse left a confession beneath the altar. Reading it aloud suppresses all Silt Servants for one round and proves Orris was deliberately saved while workers were abandoned. Characters may spend one Pressure mark to open the emergency stair or proceed directly into the Heart Cistern through a flooded grate.
7. The Heart Cistern
The Curator forms from black water and index chains. At initiative count 20, one valve opens, closes, or reverses flow. The party must earn four DC 15 Athletics, Arcana, Investigation, or thieves’ tools successes across three valve stations. The Curator can also be defeated or rewritten by placing the true charter and master index in its central cradle. At 20 hit points, it accepts a complete record and releases Orris.
8. Resolution
The diving bell lifts Orris, the charter, and surviving characters to daylight. If the valves were aligned, Hale House vents harmlessly and its dead become still. If the Curator was destroyed, the house collapses after the escape, but the charter survives. The valve sequence points to Widow’s Gate at the old dam, while the heist and rescue remain fully resolved.
NPCs and Monsters
| NPC or Monster | Statistics | Key Abilities and Table Notes |
|---|---|---|
| Ilyra Fen | Medium humanoid; AC 15, HP 45, speed 30 ft. | Arcana +6, Investigation +7, tinker’s tools +8. From the bell, she can cancel one Pressure mark or move the return cable once per adventure. |
| Orris Hale | Small humanoid; AC 11, HP 14, speed 25 ft. | Investigation +5 and Perception +4. Orris can use speaking tubes to distract one house creature, imposing disadvantage on its next attack. He hides rather than fights. |
| Drowned Curator | Large undead; AC 17, HP 118, swim 40 ft. | Index Chain +8 deals 2d8 + 5 cold and grapples. Redact Memory, DC 16 Intelligence save, removes one proficiency until end of next turn. Yields at 20 HP. |
| Portrait Hunger | Medium aberration; AC 15, HP 44, climb 30 ft. | Painted Claw +6 deals 2d6 + 3 psychic. Steal Memory, DC 14 Wisdom save, grants advantage on its next attack. Rotating its empty frame restrains it for one round. |
| Silt Servant | Medium construct; AC 16, HP 52, speed 25 ft., swim 25 ft. | Serving Blade +6 deals 1d8 + 4 slashing. Formal Order, DC 14 Deception, can redirect it for one round. It stops attacking anyone performing a plausible household task. |
Rewards
- 1,000 gp from Ilyra’s salvage consortium, plus 300 gp in recovered silver if the manor remains structurally stable.
- Tideglass Key: This glass key opens mundane locks underwater. Once per dawn, it creates a 20-foot-radius sphere of calm water for 10 minutes; currents cannot enter the sphere.
- The True Charter: Publishing it clears the flood victims’ names and grants advantage on one social check with Hollowmere officials.
Scaling the Adventure
For a 6th-level party, reduce the Curator to 98 hit points and remove one Portrait Hunger. For an 8th-level party, add a Silt Servant to the Heart Cistern and raise Redact Memory to DC 17. For a shorter session, Ilyra’s service key opens the Servants’ Gallery and Orris waits in the Nursery instead of the Air Pocket.
Underwater-Manor-Horror-Themed Table Gear
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- Underwater ruins battle map. Show flooded rooms, air pockets, and shifting safe routes through Hale House.
- Miniature brass valve wheels. Give players physical controls to assign while the Heart Cistern fills.
- Diving bell miniature. Mark the party’s lifeline and make cable failures immediately visible.