diff --git a/app.py b/app.py
index ceb2b1f..af2972a 100644
--- a/app.py
+++ b/app.py
@@ -56,7 +56,8 @@ class Store:
             db.execute("CREATE TABLE IF NOT EXISTS world (id INTEGER PRIMARY KEY CHECK (id = 1), data TEXT NOT NULL)")
             row = db.execute("SELECT data FROM world WHERE id = 1").fetchone()
         if row:
-            self.world = game.migrate(json.loads(row[0]))
+            world = json.loads(row[0])
+            self.world = game.migrate(world, time.time() + world["config"].get("clock_offset", 0))
             self.world["config"]["speed"] = speed
         else:
             self.world = game.new_world(time.time(), speed)
diff --git a/game.py b/game.py
index fac4b93..aa5a373 100644
--- a/game.py
+++ b/game.py
@@ -409,8 +409,9 @@ def new_world(now: float, speed: float = 1.0) -> dict:
     }
 
 
-def migrate(world: dict) -> dict:
+def migrate(world: dict, now: float | None = None) -> dict:
     """Bring a saved world up to the current shape. Never loses anything."""
+    now = now or world["city"]["last_tick"]
     if world.get("version", 1) < 2:
         city = world["city"]
         for building in city["buildings"].values():
@@ -419,7 +420,6 @@ def migrate(world: dict) -> dict:
         city.setdefault("tier", 0)
         world["version"] = 2
     if world["version"] < 3:
-        now = world["city"]["last_tick"]
         for player in world["players"].values():
             for skill in SKILL_IDS:
                 player["xp"].setdefault(skill, 0)
@@ -430,7 +430,7 @@ def migrate(world: dict) -> dict:
             player.setdefault("hp_at", now)
         world["version"] = 3
     if world["version"] < 4:
-        _sell_useless_stock(world, world["city"]["last_tick"])
+        _sell_useless_stock(world, now)
         world["version"] = 4
     return world