diff --git a/core/src/com/unciv/logic/civilization/diplomacy/DiplomacyManager.kt b/core/src/com/unciv/logic/civilization/diplomacy/DiplomacyManager.kt
index 02a39169a9..94ea52db6c 100644
--- a/core/src/com/unciv/logic/civilization/diplomacy/DiplomacyManager.kt
+++ b/core/src/com/unciv/logic/civilization/diplomacy/DiplomacyManager.kt
@@ -543,7 +543,8 @@ class DiplomacyManager() : IsPartOfGameInfoSerialization {
         flagsCountdown[flag.name] = amount
     }
 
-    @Readonly fun getFlag(flag: DiplomacyFlags) = flagsCountdown[flag.name]!!
+    /** 0 indicates 'flag does not exist' */
+    @Readonly fun getFlag(flag: DiplomacyFlags) = flagsCountdown[flag.name] ?: 0
     fun removeFlag(flag: DiplomacyFlags) {
         flagsCountdown.remove(flag.name)
     }