diff --git a/src/simulator/Cargo.lock b/src/simulator/Cargo.lock
index 455696d0..cb09e635 100644
--- a/src/simulator/Cargo.lock
+++ b/src/simulator/Cargo.lock
@@ -941,6 +941,17 @@ dependencies = [
  "tracing-subscriber",
 ]
 
+[[package]]
+name = "mc-replay"
+version = "0.1.0"
+dependencies = [
+ "bincode",
+ "serde",
+ "serde_json",
+ "tempfile",
+ "uuid",
+]
+
 [[package]]
 name = "mc-sim"
 version = "0.1.0"
@@ -1770,6 +1781,7 @@ checksum = "5ac8b6f42ead25368cf5b098aeb3dc8a1a2c05a3eee8a9a1a68c640edbfc79d9"
 dependencies = [
  "getrandom 0.4.2",
  "js-sys",
+ "serde_core",
  "wasm-bindgen",
 ]
 
diff --git a/src/simulator/Cargo.toml b/src/simulator/Cargo.toml
index 189d7004..942186f6 100644
--- a/src/simulator/Cargo.toml
+++ b/src/simulator/Cargo.toml
@@ -21,6 +21,7 @@ members = [
     "crates/mc-ecology",
     "crates/mc-sim",
     "crates/mc-mcts-service",
+    "crates/mc-replay",
     "api-wasm",
     "api-gdext",
     "tests/integration",
diff --git a/src/simulator/crates/mc-replay/Cargo.toml b/src/simulator/crates/mc-replay/Cargo.toml
new file mode 100644
index 00000000..4877e405
--- /dev/null
+++ b/src/simulator/crates/mc-replay/Cargo.toml
@@ -0,0 +1,27 @@
+[package]
+name    = "mc-replay"
+version = "0.1.0"
+edition = "2021"
+
+# `mc-replay` owns `GameHistory`, `TurnSnapshot`, `TurnEvent`,
+# `TurnEventCollector`, and the on-disk archive read/write surface that the
+# Statistics modal, end-of-game summary, and Past Games index all consume.
+#
+# It deliberately depends on no other simulator crate today: the upstream
+# strong-id types (ClanId, UnitKind, WonderId, TechId, EraId, MapDescriptor,
+# WorldSnapshot) are still in flux across the workspace, so this crate carries
+# its own newtype wrappers (see `ids.rs`). Each TODO in `ids.rs` names the
+# upstream crate that should eventually supply the canonical type — at which
+# point the wrapper here becomes a re-export.
+
+[dependencies]
+serde      = { workspace = true }
+serde_json = { workspace = true }
+bincode    = { version = "2", features = ["serde"] }
+uuid       = { version = "1", features = ["serde", "v4"] }
+
+[dev-dependencies]
+tempfile = "3"
+
+[lints]
+workspace = true