diff --git a/game/modules/tome/class/generator/actor/ValleyMoon.lua b/game/modules/tome/class/generator/actor/ValleyMoon.lua
index b0295c4c48e89fcca70a66df0d876cc6f68a3e41..95bea53cfe2b8bb02c10209958e1e764c1ebbdf2 100644
--- a/game/modules/tome/class/generator/actor/ValleyMoon.lua
+++ b/game/modules/tome/class/generator/actor/ValleyMoon.lua
@@ -89,7 +89,7 @@ function _M:generateOne()
 			x = spot.x y = spot.y
 			if m.unique then -- make room for the boss
 				local a = self.level.map(x, y, Map.ACTOR)
-				if not a.unique then a:die() end
+				if a and not a.unique then a:die() end
 			end
 			tries = tries + 1
 		end