diff --git a/src/main/java/me/topchetoeu/jscript/compilation/scope/VariableIndex.java b/src/main/java/me/topchetoeu/jscript/compilation/scope/VariableIndex.java
index 1eee91b..ed54ce5 100644
--- a/src/main/java/me/topchetoeu/jscript/compilation/scope/VariableIndex.java
+++ b/src/main/java/me/topchetoeu/jscript/compilation/scope/VariableIndex.java
@@ -39,7 +39,7 @@ public final class VariableIndex {
 	}
 	public final Instruction toSet(boolean keep) {
 		switch (type) {
-			case CAPTURES: return Instruction.storeVar(index, keep, false);
+			case CAPTURES: return Instruction.storeVar(~index, keep, false);
 			case CAPTURABLES: return Instruction.storeVar(index, keep, false);
 			case LOCALS: return Instruction.storeVar(index, keep, false);
 			default: throw new UnsupportedOperationException("Unknown index type " + type);