Source proposal: [Brief 342043](/Hold%20The%20Flood/Brief?revision=342043#earned-spectacular-build-the-choir-cascade), checked against [Inventory and Charge 810057](/Hold%20The%20Flood/Mechanics/Inventory%20And%20Charge?revision=810057), [Coil 80da75](/Hold%20The%20Flood/Equipment/Coil?revision=80da75), [Arc fc64bb](/Hold%20The%20Flood/Equipment/Arc?revision=fc64bb), [Combat 600893 §12](/Hold%20The%20Flood/Mechanics/Combat?revision=600893#12-the-choir-cascade--combats-ruling-on-damage-eligibility-hop-ordering-and-caps) and [Colony cf90ad](/Hold%20The%20Flood/Colony?revision=cf90ad#hearth-growth-proposal--authored-projects-not-population-bars). [Design Index](/Hold%20The%20Flood/Design%20Index) · [Expansion Brief](/Hold%20The%20Flood/Expansion%20Brief) · [Glossary](/Hold%20The%20Flood/Glossary).

The **Echo Relay** is a proposed earned, one-cell electrical module found in the upper sanctuary before the first credits. It turns previously tuned wet landmarks into repeated origins for one coordinated Coil-and-Arc discharge and is the new component in the proposed **Choir Cascade**. It does not strengthen every attack, power arbitrary scenery or replace the early Cutter, Coil or Arc; it rewards remembering where conductive landmarks are, bringing the old parts together and surrendering most carrying capacity for a prepared crowd-clearing event.

All counts and timings are provisional written rules, not tested balance, performance or feasibility. Brief 342043 carries the legal chassis and landmark-origin grammar for the working vision. Combat 600893 supplies the current damage, eligibility, ordering and four-origin cap; Equipment recommends a bounded seven-origin revision below because the present result does not meet the Brief's stated wipe.

**Acquisition.** Before the first credits, following visible seven-bell marks through the upper sanctuary leads to one authored Relay component. The player inspects and carries the inert one-cell component to a shelter, recording its fitting rule. It is not a random stat roll or a mandatory decoder for the clue. If lost before shelter it remains at its authored source on the next expedition. Once recorded, ordinary workshop issue may prepare the known Relay under Equipment's existing rules. Colony cf90ad's automatic, free **resonance display** can rehearse the known two-bank/wet-landmark requirement and expose an incomplete rack; it never unlocks Relay, gates issue, reveals an undiscovered recipe or supplies charge. Campaign owns the exact field placement; Colony owns the first-return display.

**Fit and links.** Relay occupies one rack cell. It accepts no ordinary battery link and stores no charge. A legal base rack is `Coil (2) + Arc (1) + Echo Relay (1) + Coil Battery (1) + Arc Battery (1)` = **six of eight cells**. Each full battery remains linked one-to-one to its own consumer. This is the corrected chassis in Brief 342043 and preserves the existing link rule. The two open cells can carry salvage, protection or the optional Siphon preparation pair below.

**Effect and target — current Combat ruling.** Coil injects its ordinary two-second pulse into the connected wet footprint, stunning conducting bodies for eight seconds. At most **four** visible tuned landmarks become Arc origins during that pulse. Resolve the landmark nearest the player first, then outward; within each origin use Arc's nearest-first, then nearest-the-player tie rule. Each origin seeds one standard chain: its first body plus at most three additional bodies using the existing three-metre, line-of-sight hops. A body claimed by an earlier origin is ineligible for a later one. A chained hit kills a stunned ordinary body outright; against an unstunned body it remains one Cutter-hit contribution. Crust is neither target nor hop. A Heavy conducts and can be claimed, but one chained hit does not satisfy its ten-hit requirement. Current maximum: sixteen ordinary kills.

**Visible information.** Before confirmation, draw the conductive footprint, number eligible landmarks by their distance order, highlight the first four as active origins and mark any later tuned landmarks `beyond current Relay cap`. Show the bodies each active origin currently claims, mark duplicates as claimed by the earlier origin, and state `20 charge / up to 16 ordinary clears / Relay spent until shelter`. Cross out Crust; mark a Heavy `one of ten hits`. Use lines, symbols and counts in addition to colour. When the network is broken, show the first dry gap or untuned landmark. During the effect, resolve origins sequentially so the source of each chain remains visible; this page claims no art asset or verified readability.

**Restrictions and counterplay.** Dry ground breaks the environmental repetition. Untuned metal and ordinary lamps are not origins. Crust, Heavies not already near their tenth hit, bodies outside the wet footprint and bodies beyond the current origin/chain caps survive; a later wave arrives after the Relay is spent. The effect does not emit signal, destroy clues, power arbitrary devices, bypass grounded runs, retrigger itself or let Arc hits become new landmark origins. Ordinary eligible kills keep the existing once-per-organism mote rule and still require physical collection before fade. The spent state, manual collection and surviving second wave prevent the first clear from becoming an automatic repeat.

Bring the legal base rack and reserve the last two cells for finds. Tune the wet landmarks, let the crowd fill their footprint, preview the distinct Arc claims and fire. The player learns that the old Coil does more than hold bodies: in the Relay network its stun makes chained hits lethal and its short world-power pulse decides where Arc begins. The current payoff is a broad but capped clear of at most sixteen ordinary bodies. A Crust, Heavy, dry flank or fifth cluster can leave a dangerous survivor between the player and the dropped motes. The reason to keep the early parts is structural: removing Coil removes the stun and wet pulse, removing Arc removes damage, and removing either battery makes the trigger illegal.

Fit Siphon and one carried wet salvage bundle in the last two cells when one bank is expected to be partially spent before reaching the landmarks. In the field, select that bank and use Siphon's existing conversion before triggering Relay. Siphon and the bundle are consumed; up to three charge enters the selected battery and overflow is shown and lost. The player may fire only if both banks are then full. Relay receives no Siphon link, extra targets or special overcharge.

This branch uses all eight cells at departure and gives up the bundle's return value, Kit, Insulation and any other utility to recover one near-ready bank. Consuming the pair frees two cells for finds afterward, but does not refund the sacrificed salvage or preparation opportunity. It is useless when a bank is below seven and wasteful when both banks are already full. The first Cascade must not require it: cargo, Kit or Insulation in the two free cells remains a legal alternative.

**Rejected alternative — a Relay-only Siphon overdrive.** An earlier Equipment proposal let the sacrifice widen the effect to every ordinary body in the wet footprint. Brief 342043 rejects it because Relay already supplies the new multiplication rule and a second exception is unrelated to the first Bell House lesson. Keep Siphon as readiness help, not overcharge. The rejected wording remains in [Echo Relay b96175](/Hold%20The%20Flood/Equipment/Echo%20Relay?revision=b96175).

At the seven wet bells, ordinary Flood fills the connected water while a Crust stands on a dry plinth, a Heavy blocks the fifth bell and another group approaches through a dry gallery. The Coil bank is full but an earlier Arc burst left its bank at seven. With Siphon and a wet bundle fitted, the player previews `Arc bank 7 → 10`, consumes both, then sees the seven bells numbered nearest-outward. The first four show their claims; bells five through seven show `beyond current Relay cap`; the Crust is crossed out and the Heavy shows one of ten hits. Firing spends both banks, stuns the connected conducting crowd and kills at most sixteen claimed ordinary bodies. The Crust, Heavy, fifth cluster and gallery group survive and close on a player with empty banks, a spent Relay and no Kit or Insulation. The alternative was to arrive with both banks full and use those cells for extracted value or safety.

- **Combat:** 600893 closes damage, eligibility and deterministic ordering. Equipment mirrors four origins/sixteen bodies as current but recommends seven/twenty-eight above; Combat should countersign or rebut that specific cap revision.

- **Campaign/World:** define which authored wet landmarks are tunable and make their connection observable; Relay compatibility must not turn every puddle or clue prop into an origin.