diff --git a/runelite-api/src/main/java/net/runelite/api/Client.java b/runelite-api/src/main/java/net/runelite/api/Client.java
index 4da908f480..a90a8738b1 100644
--- a/runelite-api/src/main/java/net/runelite/api/Client.java
+++ b/runelite-api/src/main/java/net/runelite/api/Client.java
@@ -39,6 +39,8 @@ public interface Client extends GameEngine
 
 	List<NPC> getNpcs();
 
+	NPC[] getCachedNPCs();
+
 	int getBoostedSkillLevel(Skill skill);
 
 	int getRealSkillLevel(Skill skill);
diff --git a/runelite-api/src/main/java/net/runelite/api/NPC.java b/runelite-api/src/main/java/net/runelite/api/NPC.java
index 9fcf4ff919..10497c7a4e 100644
--- a/runelite-api/src/main/java/net/runelite/api/NPC.java
+++ b/runelite-api/src/main/java/net/runelite/api/NPC.java
@@ -34,4 +34,5 @@ public interface NPC extends Actor
 	@Override
 	int getCombatLevel();
 
+	int getIndex();
 }
diff --git a/runelite-client/src/main/java/net/runelite/client/plugins/opponentinfo/OpponentInfoOverlay.java b/runelite-client/src/main/java/net/runelite/client/plugins/opponentinfo/OpponentInfoOverlay.java
index 51b2c5f163..0156805cb2 100644
--- a/runelite-client/src/main/java/net/runelite/client/plugins/opponentinfo/OpponentInfoOverlay.java
+++ b/runelite-client/src/main/java/net/runelite/client/plugins/opponentinfo/OpponentInfoOverlay.java
@@ -37,6 +37,7 @@ import java.util.Map;
 import javax.inject.Inject;
 import net.runelite.api.Actor;
 import net.runelite.api.Client;
+import net.runelite.api.NPC;
 import net.runelite.api.Player;
 import net.runelite.api.Varbits;
 import net.runelite.client.ui.overlay.Overlay;
@@ -60,6 +61,8 @@ class OpponentInfoOverlay extends Overlay
 	private static final Duration WAIT = Duration.ofSeconds(3);
 
 	private final Client client;
+	private final NPC[] clientNpcs;
+
 	private Integer lastMaxHealth;
 	private DecimalFormat df = new DecimalFormat("0.0");
 	private float lastRatio = 0;
@@ -67,6 +70,7 @@ class OpponentInfoOverlay extends Overlay
 	private String opponentName;
 	private String opponentsOpponentName;
 	private Map<String, Integer> oppInfoHealth = OpponentInfoPlugin.loadNpcHealth();
+	private NPC lastOpponent;
 
 	@Inject
 	OpponentInfoOverlay(Client client)
@@ -74,6 +78,7 @@ class OpponentInfoOverlay extends Overlay
 		setPosition(OverlayPosition.TOP_LEFT);
 		setPriority(OverlayPriority.HIGH);
 		this.client = client;
+		this.clientNpcs = client.getCachedNPCs();
 	}
 
 	private Actor getOpponent()
@@ -92,6 +97,25 @@ class OpponentInfoOverlay extends Overlay
 	{
 		Actor opponent = getOpponent();
 
+		// If opponent is null, try to use last opponent
+		if (opponent == null)
+		{
+			if (lastOpponent != null && clientNpcs[lastOpponent.getIndex()] != lastOpponent)
+			{
+				// lastOpponent is no longer valid
+				lastOpponent = null;
+			}
+			else
+			{
+				opponent = lastOpponent;
+			}
+		}
+		else
+		{
+			// Update last opponent
+			lastOpponent = opponent instanceof NPC ? (NPC) opponent : null;
+		}
+
 		if (opponent != null && opponent.getHealth() > 0)
 		{
 			lastTime = Instant.now();
diff --git a/runelite-mixins/src/main/java/net/runelite/mixins/RSClientMixin.java b/runelite-mixins/src/main/java/net/runelite/mixins/RSClientMixin.java
index 94cd998160..70eadca682 100644
--- a/runelite-mixins/src/main/java/net/runelite/mixins/RSClientMixin.java
+++ b/runelite-mixins/src/main/java/net/runelite/mixins/RSClientMixin.java
@@ -65,6 +65,7 @@ import net.runelite.rs.api.RSDeque;
 import net.runelite.rs.api.RSHashTable;
 import net.runelite.rs.api.RSIndexedSprite;
 import net.runelite.rs.api.RSItemContainer;
+import net.runelite.rs.api.RSNPC;
 import net.runelite.rs.api.RSName;
 import net.runelite.rs.api.RSWidget;
 
@@ -494,6 +495,24 @@ public abstract class RSClientMixin implements RSClient
 		eventBus.post(gameStateChange);
 	}
 
+
+	@FieldHook("cachedNPCs")
+	@Inject
+	public static void cachedNPCsChanged(int idx)
+	{
+		RSNPC[] cachedNPCs = client.getCachedNPCs();
+		if (idx < 0 || idx >= cachedNPCs.length)
+		{
+			return;
+		}
+
+		RSNPC npc = cachedNPCs[idx];
+		if (npc != null)
+		{
+			npc.setIndex(idx);
+		}
+	}
+
 	@Inject
 	@FieldHook("grandExchangeOffers")
 	public static void onGrandExchangeOffersChanged(int idx)
diff --git a/runelite-mixins/src/main/java/net/runelite/mixins/RSNPCMixin.java b/runelite-mixins/src/main/java/net/runelite/mixins/RSNPCMixin.java
index 0b08a1cc7d..d052b8c6e2 100644
--- a/runelite-mixins/src/main/java/net/runelite/mixins/RSNPCMixin.java
+++ b/runelite-mixins/src/main/java/net/runelite/mixins/RSNPCMixin.java
@@ -32,6 +32,9 @@ import net.runelite.rs.api.RSNPCComposition;
 @Mixin(RSNPC.class)
 public abstract class RSNPCMixin implements RSNPC
 {
+	@Inject
+	private int npcIndex;
+
 	@Inject
 	@Override
 	public int getId()
@@ -55,4 +58,18 @@ public abstract class RSNPCMixin implements RSNPC
 		RSNPCComposition composition = getComposition();
 		return composition == null ? -1 : composition.getCombatLevel();
 	}
+
+	@Inject
+	@Override
+	public int getIndex()
+	{
+		return npcIndex;
+	}
+
+	@Inject
+	@Override
+	public void setIndex(int id)
+	{
+		npcIndex = id;
+	}
 }
diff --git a/runescape-api/src/main/java/net/runelite/rs/api/RSClient.java b/runescape-api/src/main/java/net/runelite/rs/api/RSClient.java
index 5a099109ea..2fa2e4940f 100644
--- a/runescape-api/src/main/java/net/runelite/rs/api/RSClient.java
+++ b/runescape-api/src/main/java/net/runelite/rs/api/RSClient.java
@@ -129,6 +129,7 @@ public interface RSClient extends RSGameEngine, Client
 	int[] getNpcIndices();
 
 	@Import("cachedNPCs")
+	@Override
 	RSNPC[] getCachedNPCs();
 
 	@Import("collisionMaps")
diff --git a/runescape-api/src/main/java/net/runelite/rs/api/RSNPC.java b/runescape-api/src/main/java/net/runelite/rs/api/RSNPC.java
index 9419850d27..a401cf3cf5 100644
--- a/runescape-api/src/main/java/net/runelite/rs/api/RSNPC.java
+++ b/runescape-api/src/main/java/net/runelite/rs/api/RSNPC.java
@@ -31,4 +31,9 @@ public interface RSNPC extends RSActor, NPC
 {
 	@Import("composition")
 	RSNPCComposition getComposition();
+
+	@Override
+	int getIndex();
+
+	void setIndex(int id);
 }