Source proposal: [Brief 342043](/Hold%20The%20Flood/Brief?revision=342043#earned-spectacular-build-the-choir-cascade), checked against [PMR011 726f09](/Hold%20The%20Flood/PM%20Reviews?revision=726f09#pmr011-current-review-checkpoint), [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. Combat 600893 supplies the damage and eligibility proposal; PMR011 selects seven tuned origins provisionally and requests an explicit Relay-only execution rule, deterministic ties and a same-scene comparison.

**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 — PMR011 provisional synthesis.** Coil injects its ordinary two-second pulse into the connected wet footprint, stunning conducting bodies for eight seconds. Up to **seven** visible tuned landmarks become Arc origins during that pulse. Resolve the landmark nearest the player first, then outward; exact landmark-distance ties use the recorded seven-part tuning order. Within each origin, choose the nearest eligible body, then use Arc's nearest-first / nearest-the-player tie rule for up to three additional three-metre, line-of-sight hops. A body claimed by an earlier origin is ineligible for a later one.

Only a **Relay-origin chain during this same activation** executes a Coil-stunned ordinary body. Cutter-origin chains from an ordinary Arc burst remain one Cutter-hit contribution even if the target was stunned earlier; Coil + Arc without Relay therefore keeps its existing rules. Crust is neither target nor hop. A Heavy conducts and can be claimed, but is not an ordinary body for this interaction: one Relay-origin hit does not satisfy its ten-hit requirement. Current maximum: twenty-eight ordinary kills. This is a narrow combination rule, not a global change to Stunned or Arc.

**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 Relay-origin chains lethal and its short world-power pulse decides where Arc begins. The current payoff is a bounded clear of at most twenty-eight ordinary bodies. A Crust, Heavy, dry flank, eighth cluster or poor spacing 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).

**Paying for the moment.** Both banks begin empty. The furnace approach offers at least twenty fresh ordinary bodies across two optional side galleries; fighting within pickup range can fill the two banks under the existing once-per-body rule, but costs time/exposure and yields no persistent salvage. A player who reaches one bank at seven may instead consume fitted Siphon + one wet bundle for the last three charge, sacrificing both final cells and the bundle's return value. No free Hearth charge is invented. At the furnace, confirming Relay spends all twenty charge and its one activation. Seven chains resolve in previewed order and clear the twenty-eight ordinary bodies; the Crust, Heavy and forecast later wave remain.

**Consequence beyond killing.** The clear exposes three manual furnace dampers around the ring. Each takes a short hold and the route between all three exceeds Coil's eight-second stun window; a visible later-wave forecast is long enough for the proposed Relay clear to buy the circuit, not guaranteed safety afterward. Turning all three restarts the furnace and earns the apparent-ending consequence in Brief 342043. Exact holds, path time and arrival interval belong to Campaign/Combat and remain provisional; the required relationship is `more than 8 seconds to complete the circuit, less than the visible post-clear interval`, not a hidden timer.

**Same scene without Relay.** Coil alone stuns all conducting bodies for eight seconds but kills none; the three-damper circuit cannot be assumed complete before recovery. Coil + ordinary Arc can then spend its separate bank, but only Cutter-origin chains occur: each hop remains one Cutter-hit contribution and the player must stay near the crowd long enough for automatic Cutter attacks rather than simply run the dampers. It may thin the room, but it receives neither seven remote origins nor Relay-only execution and cannot claim the written twenty-eight-body clear. The Relay therefore changes the action and outcome rather than serving as a ticket for an interaction Coil + Arc already had.

**Credible alternative.** Combat's earlier four-origin/sixteen-body version is easier to read and leaves more of the first wave active. PMR011 declines it provisionally because it leaves three learned bells inert and does not earn the written payoff. Keep the seven-origin cap for this pass, with sequential cues and pre-fire claims; if the result later proves unreadable in an authorized play phase, cap reduction is the first tuning candidate. No tested readability or spectacle is claimed now.

- **Combat:** countersign or revise the Relay-only execution boundary, exact landmark-distance tie and seven-origin furnace composition. Ordinary Coil + Arc remains unchanged.

- **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.