diff --git a/Core/Cpu/Z80.cs b/Core/Cpu/Z80.cs
index 83f990c..7a5684c 100644
--- a/Core/Cpu/Z80.cs
+++ b/Core/Cpu/Z80.cs
@@ -1434,6 +1434,10 @@ namespace Core.Cpu
                     }
                 // --- SBC HL, rr ---
                 case 0x42: SbcHl(BC.Word); return 15;
+                case 0x45: // RETN (Return from NMI)
+                    IFF1 = IFF2; // Restore the interrupt state
+                    PC = Pop();  // Jump back to where we came from
+                    return 14;
                 case 0x52: SbcHl(DE.Word); return 15;
                 case 0x62: SbcHl(HL.Word); return 15;
                 case 0x72: SbcHl(SP); return 15;