diff --git a/packages/engine/src/game.ts b/packages/engine/src/game.ts
index c28f0b1..34ca4b2 100644
--- a/packages/engine/src/game.ts
+++ b/packages/engine/src/game.ts
@@ -1937,9 +1937,15 @@ const CARD_EFFECTS: Record<string, AttackEffect | NeutralEffect | CounterEffect>
       if (cmd.target?.kind === "edge") {
         const { cell, side } = cmd.target;
         const key = edgeKey(cell, side);
-        if (view.edges[key] !== "wall") return "that is not a stone wall";
+        // Doors are "small entryways in a stone wall" — stone melts as
+        // stone (rev 38; older ledgers had refused doors and replay so).
+        const current = view.edges[key];
+        const meltable = current === "wall" ||
+          ((state.config.deckRev ?? 1) >= 38 && current === "door");
+        if (!meltable) return "that is not a stone wall";
         if (!losToEdge(view, caster.position, cell, side)) return "no line of sight";
         state.edgeOverrides[key] = "open";
+        delete state.doorStates[key];
         delete state.createdEdges[key];
         events.push({ type: "stoneTurnedToWater", caster: caster.id, at: null, edge: { cell, side } });
         // "Wall turns into a WATERWALL with a range and damage of 2."
diff --git a/packages/engine/test/expansion-terrain.test.ts b/packages/engine/test/expansion-terrain.test.ts
index 133d815..8b6299e 100644
--- a/packages/engine/test/expansion-terrain.test.ts
+++ b/packages/engine/test/expansion-terrain.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it } from "vitest";
 import { applyCommand, activePlayer, boardView, createGame, gameLos } from "../src/game";
-import { cellKey, edgeKey, SIDES, stepTarget, type Cell } from "../src/board";
+import { cellKey, edgeKey, SIDES, stepTarget, type Cell, type Side } from "../src/board";
 import type { CardInstance } from "../src/cards";
 import { eligibleCellsFor, sightedCellsFor, viewFor } from "../src/view";
 import { newExpansionGame as newGame, must, giveCard, emptyNeighborCell } from "./helpers";
@@ -161,6 +161,40 @@ describe("expansion terrain", () => {
     expect(state.squareContents[cellKey(spot.cell)]).toBeUndefined();
     // Wave side effects vary by geometry; the melt itself is the pinned behavior.
   });
+
+  it("stone to water melts a door from rev 38 — a small entryway in a stone wall", () => {
+    for (const deckRev of [37, 38]) {
+      const { state } = createGame({
+        playerIds: ["alice", "bob"], seed: 42, sets: ["basic", "expansion1"], deckRev,
+      });
+      const me = activePlayer(state);
+      const board = boardView(state);
+      // Stand the caster at some door and melt it point-blank.
+      let doorAt: { cell: Cell; side: Side } | null = null;
+      outer: for (const k of Object.keys(board.cells)) {
+        const [x, y] = k.split(",").map(Number) as [number, number];
+        for (const side of SIDES) {
+          if (board.edges[edgeKey({ x, y }, side)] === "door") {
+            doorAt = { cell: { x, y }, side };
+            break outer;
+          }
+        }
+      }
+      if (!doorAt) throw new Error("setup: no door on this board");
+      me.position = { ...doorAt.cell };
+      const stw = giveCard(state, me.id, "stone-to-water", "SW", 0);
+      const r = applyCommand(state, me.id, {
+        type: "cast", instanceId: stw.instanceId,
+        target: { kind: "edge", cell: doorAt.cell, side: doorAt.side },
+      });
+      expect(r.ok).toBe(deckRev >= 38);
+      if (r.ok) {
+        const key = edgeKey(doorAt.cell, doorAt.side);
+        expect(boardView(r.state).edges[key] ?? "open").toBe("open");
+        expect(r.state.doorStates[key]).toBeUndefined();
+      }
+    }
+  });
 });
 
 describe("eligibility dimming mirrors the engine", () => {
diff --git a/packages/server/src/rooms.ts b/packages/server/src/rooms.ts
index b61357f..165fa95 100644
--- a/packages/server/src/rooms.ts
+++ b/packages/server/src/rooms.ts
@@ -54,7 +54,7 @@ export interface Room {
 const rooms = new Map<string, Room>();
 
 /** Rules revision new games are dealt under (stored games keep their own). */
-const RULES_REV = 37;
+const RULES_REV = 38;
 
 const ROOM_CODE_ALPHABET = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789";
 
diff --git a/packages/web/src/App.svelte b/packages/web/src/App.svelte
index 57fc018..291d877 100644
--- a/packages/web/src/App.svelte
+++ b/packages/web/src/App.svelte
@@ -282,7 +282,7 @@
     "remove-lock": "click a door to strip its lock for good",
     "create-door": "click a wall for the new door",
     "warp-wand": "click a wall to warp it open",
-    "stone-to-water": "click a stone wall, or a stone-filled square",
+    "stone-to-water": "click a stone wall or door, or a stone-filled square",
     "thumb-of-god": "aim the die at a square in sight — it may drift on impact",
     "dispel-creation": "click the creation — a square, a creature, or a conjured wall",
   };