Adventure Summary: A one-session heist and rescue for four to five 6th-level characters. A diplomat who exposed illegal sky-lane tolls is trapped inside a clockwork embassy, and the party must extract her testimony plus the official counterseal before the building seals for a seven-day audit.
Brass Comet Saga: Part 2 of 4. This adventure stands alone. Previously: Rescue at the Skyglass Auction. The saga continues with The Midnight Train to Starfall.
Overview
Whistleblower Sera Nox sends a paper gear through a canal grate with a warning: the Clockwork Embassy will erase her testimony at midnight. Nyra Vale offers 900 gp for Sera, the route cipher, and a clean exit that does not ignite a diplomatic conflict.
Track Rotation from zero to four. Add one after a failed restricted-area check or every twenty minutes. At each increase, the Rotating Balcony turns ninety degrees. At Rotation 4, the Clockface Exit opens for three rounds, then the embassy enters total lockdown.
Background
The embassy certifies commercial navigation seals. Sera discovered Ambassador Tamsin Quill sold Magnate Orin Veyr a master route cipher that can falsify ownership of the Brass Comet’s path. Quill confined Sera behind an Ink Ward and ordered Warden Helix to protect the records until they can be altered.
Standalone hook: Nyra provides a canal skiff, servant uniforms, and Sera’s paper gear. Rescuing Sera and obtaining one valid counterseal gives the city enough evidence to void the illegal toll contracts, fully resolving the embassy job.
Characters
- Nyra Vale: The courier coordinates the canal approach and waits beneath the Clockface Exit.
- Sera Nox: A meticulous junior diplomat who can identify the authentic route cipher.
- Ambassador Tamsin Quill: A composed official who values her career more than Veyr’s scheme.
- Warden Helix: A silver construct that interprets every sealed order literally.
Setting
The labeled map connects the Canal Gate, Rotating Balcony, Seal Archive, Ink Ward, Ambassador’s Hall, and Clockface Exit. The balcony moves at Rotation increases. A creature on its edge must make a DC 13 Dexterity save or slide 10 feet, stopping safely at the railing.
Blue ink lines mark restricted areas. Crossing a line without a staff seal triggers a soft chime and requires DC 14 Arcana, Performance, or thieves’ tools to suppress. Three chimes in one scene add one Rotation.
Plot Outline
The party enters through the Canal Gate, rides or manipulates the Rotating Balcony, steals a counterseal from the archive, frees Sera from the Ink Ward, confronts Quill and Helix, and escapes through the opening Clockface with the witness and evidence secure.
1. Service Entrance
At the Canal Gate, a clerk asks for the evening work order. A DC 14 Deception, forgery kit, or Persuasion check passes inspection. Failure adds Rotation but the paper gear unfolds into Sera’s emergency maintenance code, opening the gate after one minute.
2. Balcony in Motion
The party needs three DC 14 Acrobatics, Arcana, or Investigation successes to align the balcony with the Seal Archive. Each failure rotates it to the wrong room and introduces an Inkwing Drone. Disabling the gear brake holds the balcony for ten minutes but adds Rotation.
3. The Counterseal
Six seals rest beneath mirrored glass. Clues in Sera’s paper gear identify the true counterseal through three DC 15 Investigation, Insight, or calligrapher’s supplies successes before two failures. A failure activates a harmless but loud ink spray and adds Rotation.
4. Break the Ink Ward
Sera is conscious inside a circle of six ink pylons. The party can disable three pylons with DC 15 Arcana or thieves’ tools checks, use the counterseal for one automatic success, or break them at AC 14 and 15 hit points each. Each round after the first, one Drone enters from a wall hatch.
5. The Clockface Accord
Quill and Warden Helix block the exit. The party wins by defeating Helix, presenting the counterseal plus Sera’s testimony with three DC 15 Persuasion or Insight successes, or rotating the clockface through three DC 15 Athletics and Arcana successes. Quill orders Helix to stand down if shown that the cipher bears Veyr’s private mark.
6. Canal Testimony
Nyra’s skiff catches everyone beneath the opened Clockface. Sera files the counterseal before dawn, the illegal toll contracts are suspended, and Quill signs a confession or faces public charges. The recovered cipher names a midnight train, a future lead that does not leave the embassy rescue unresolved.
NPCs and Monsters
| NPC or Monster | Statistics | Key Abilities and Table Notes |
|---|---|---|
| Nyra Vale | Medium humanoid; AC 14, HP 38, speed 30 ft. | Airship Pilot and Mark an Exit support extraction. Nyra waits in the canal skiff and never abandons rescued passengers. |
| Sera Nox | Medium humanoid; AC 12, HP 31, speed 30 ft. | Investigation +6, calligrapher’s supplies +7. Authentic Seal grants advantage on one cipher or ward check. She avoids combat. |
| Ambassador Tamsin Quill | Medium humanoid; AC 14, HP 57, speed 30 ft. | Seal rod +5, 1d6 + 3 force. Diplomatic Order moves one ally. She stands down when Veyr’s mark and Sera’s testimony are both presented. |
| Warden Helix | Large construct; AC 18, HP 102, speed 30 ft. | Two seal-staff attacks +8, 2d8 + 5 force. Lockdown Pulse, DC 15 Strength. Authentic counterseal suspends one order each round. |
Rewards
- 900 gp from the city advocate’s office and lawful immunity for the embassy extraction.
- Counterseal Brooch: This uncommon brooch grants advantage on one check to identify or bypass a seal per short rest and can suppress a magical alarm for one round per dawn.
Scaling the Adventure
For 5th level, reduce Helix to 82 hit points and use one Drone at the Ink Ward. For 7th level, Helix gains 15 temporary hit points at Rotation 4. For a two-hour session, begin on the Rotating Balcony with the Canal Gate passed. For groups avoiding political detention, Sera is confined by an automated audit error that Quill concealed rather than by deliberate imprisonment.
Clockwork Embassy-Themed Table Gear
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- Brass gear terrain pieces. Show the rotating balcony and let players physically align the embassy rooms.
- Blue invisible ink kit. Create Sera’s coded paper gear and reveal the authentic counterseal clues at the table.
- Miniature wax seal props. Give each restricted door and diplomatic order a distinct, trackable seal.