diff --git a/language.txt b/language.txt
index 6438a36..ff9169d 100644
--- a/language.txt
+++ b/language.txt
@@ -59,3 +59,11 @@ VHT_QST_3_0 =
 VHT_QST_3_1 =
 	"there doesn't seem to be anything here\n"
 	"for @= right now.";
+
+VHT_QST_4_FireMask =
+	"\n\cfthere should be a fiery artifact here.";
+
+VHT_QST_4_0 =
+	"there should be a lever somewhere within.";
+VHT_QST_4_1 =
+	"the lever is pulled.";
diff --git a/vhtzs/events.zsc b/vhtzs/events.zsc
index d71b494..399fb94 100644
--- a/vhtzs/events.zsc
+++ b/vhtzs/events.zsc
@@ -21,40 +21,22 @@ class VhtEvents : StaticEventHandler {
 	override void playerDisconnected(PlayerEvent e) {
 		let p = players[e.playerNumber].mo;
 		if(p) {
-			let qh_r = VhtQuestHolder(p.findInventory("VhtQuestHolder"));
-			if(qh_r) {
-				p.removeInventory(qh_r);
-				let qh_l = vhtGetQuests();
-				if(qh_l) {
-					qh_r.m_quests.move(qh_l.m_quests);
-				}
+			let qh_ply = VhtQuestHolder(p.findInventory("VhtQuestHolder"));
+			let qh_cur = vhtGetQuests();
+			if(qh_cur == qh_ply) {
+				p.removeInventory(qh_ply);
+				qh_cur = vhtGetQuests();
+				qh_ply.m_quests.move(qh_cur.m_quests);
 			}
 		}
 	}
 	override void worldTick() {
 		m_useQuestLog = vht_player_questlog;
 		let qh = vhtGetQuests();
-		if(!qh) {
-			return;
-		}
-		for(int i = 0, j = qh.m_quests.size(); i < j; ++i) {
-			if(qh.m_quests[i]) {
-				qh.m_quests[i].vhtTick();
-			}
-		}
-		if(m_useQuestLog) {
-			m_questLog = "";
-			for(int i = 0, j = qh.m_quests.size(); i < j; ++i) {
-				if(qh.m_quests[i]) {
-					m_questLog.appendFormat(
-						"\cu- \cn%s\c-\n%s\n\n",
-						StringTable.localize(
-							qh.m_quests[i].vhtLevelInfo().levelName,
-							false
-						),
-						qh.m_quests[i].vhtDescribe()
-					);
-				}
+		if(qh) {
+			qh.vhtTick();
+			if(m_useQuestLog) {
+				m_questLog = qh.vhtDescribe();
 			}
 		}
 	}
diff --git a/vhtzs/fnplayer.zsc b/vhtzs/fn.zsc
similarity index 73%
rename from vhtzs/fnplayer.zsc
rename to vhtzs/fn.zsc
index 5091d24..a5fa712 100644
--- a/vhtzs/fnplayer.zsc
+++ b/vhtzs/fn.zsc
@@ -1,7 +1,26 @@
-class VhtFnPlayer abstract {
+class VhtFnBool abstract {
+	virtual bool vhtRun() {return false;}
+}
+
+class VhtFnBoolFuse : VhtFnBool {
+	bool      m_result;
+	VhtFnBool m_fInner;
+	VhtFnBoolFuse vhtInit(VhtFnBool fInner) {
+		m_fInner = fInner;
+		return self;
+	}
+	override bool vhtRun() {
+		if(!m_result) {
+			m_result = m_fInner.vhtRun();
+		}
+		return m_result;
+	}
+}
+
+class VhtFnPlayer : VhtFnBool abstract {
 	int m_player;
 	virtual bool vhtCall(PlayerInfo p) {return false;}
-	bool vhtRun() {
+	override bool vhtRun() {
 		for(int i = 0; i < MAXPLAYERS; ++i) {
 			if(playerInGame[i] && vhtCall(players[i])) {
 				m_player = i;
diff --git a/vhtzs/quest.zsc b/vhtzs/quest.zsc
index 25fa4f3..6308c87 100644
--- a/vhtzs/quest.zsc
+++ b/vhtzs/quest.zsc
@@ -1,5 +1,5 @@
 class VhtQuest abstract play {
-	int         m_mapNum, m_step, m_flags;
+	int         m_mapNum, m_step;
 	VhtHubQuest m_hubQuest;
 	virtual VhtQuest vhtInit(VhtHubQuest hubQuest) {
 		m_mapNum   = level.levelNum;
@@ -19,6 +19,19 @@ class VhtQuest abstract play {
 	LevelInfo vhtLevelInfo() const {
 		return LevelInfo.findLevelByNum(m_mapNum);
 	}
+	static Line vhtGetLine(int lineId) {
+		return level.lines[level.createLineIdIterator(lineId).next()];
+	}
+	static bool vhtCheckLever(int lineId) {
+		let ln = vhtGetLine(lineId);
+		if(ln) {
+			let sd = ln.sidedef[Line.FRONT];
+			if(sd && TexMan.getName(sd.getTexture(Side.MID)) ~== "SW_OL5") {
+				return true;
+			}
+		}
+		return false;
+	}
 }
 
 class VhtHubQuest : VhtQuest abstract {
@@ -34,11 +47,9 @@ class VhtHubQuest : VhtQuest abstract {
 class VhtQuest1 : VhtHubQuest {
 	VhtFnPlayer m_fStep0; // quest 1 step 0: walk into courtyard
 	VhtFnPlayer m_fStep1; // quest 1 step 1: pick up silver key
-	Line        m_lStep2; // quest 1 step 2: ring the bell
 	override void vhtInitHub() {
 		m_fStep0 = new("VhtFnPlayerInSector") .vhtInit(115);
 		m_fStep1 = new("VhtFnPlayerInvAmount").vhtInit("KeySilver", 1);
-		m_lStep2 = level.lines[level.createLineIdIterator(2).next()];
 	}
 	// same hub, but cannot return
 	override void vhtTravelled() {
@@ -46,9 +57,17 @@ class VhtQuest1 : VhtHubQuest {
 	}
 	override void vhtTick() {
 		switch(m_step) {
-		case 0: if(m_fStep0.vhtRun())                    {m_step = 1;} break;
-		case 1: if(m_fStep1.vhtRun())                    {m_step = 2;} // -->
-		case 2: if(!(m_lStep2.flags & Line.ML_BLOCKING)) {m_step = 3;} break;
+		case 0:
+			if(m_fStep0.vhtRun()) {m_step = 1;}
+			break;
+		case 1:
+			if(m_fStep1.vhtRun()) {m_step = 2;}
+			// fall through
+		case 2:
+			// quest 1 step 2: ring the bell
+			let ln = vhtGetLine(2);
+			if(ln && !(ln.flags & Line.ML_BLOCKING)) {m_step = 3;}
+			break;
 		}
 	}
 }
@@ -57,10 +76,18 @@ class VhtQuest1 : VhtHubQuest {
 class VhtQuest2 : VhtHubQuest {
 	// quest 2 step 1: 3 switches pulled in first puzzle
 	int m_guardianOfFire, m_guardianOfSteel;
+	// quest 3 puzzle item: flame mask
+	VhtFnBoolFuse m_fFlameMask;
+	override void vhtInitHub() {
+		m_fFlameMask = new("VhtFnBoolFuse").vhtInit(new("VhtFnPlayerInvAmount").vhtInit("PuzzFlameMask", 1));
+	}
+	override void vhtTick() {
+		m_fFlameMask.vhtRun();
+	}
 	override void vhtTravelled() {
 		// quest 2 step 0: return from guardian of ice
 		if(m_step == 0 && level.levelNum == m_mapNum) {
-			++m_step;
+			m_step = 1;
 		}
 	}
 	override string vhtDescribe() {
@@ -77,13 +104,38 @@ class VhtQuest3 : VhtQuest {
 	override void vhtPreTravelled() {
 		// quest 3 step 0: exit to hub
 		if(m_step == 0) {
-			++m_step;
+			m_step = 1;
 		}
 	}
 }
 
 // quest 4: guardian of fire
-class VhtQuest4 : VhtQuest {}
+class VhtQuest4 : VhtQuest {
+	override VhtQuest vhtInit(VhtHubQuest hubQuest) {
+		super.vhtInit(hubQuest);
+		return self;
+	}
+	override void vhtTick() {
+		if(level.levelNum == m_mapNum) {
+			switch(m_step) {
+			case 0:
+				// quest 4 step 0: press the switch
+				if(vhtCheckLever(2)) {
+					m_step = 1;
+					++VhtQuest2(m_hubQuest).m_guardianOfFire;
+				}
+				break;
+			}
+		}
+	}
+	override string vhtDescribe() {
+		let s = super.vhtDescribe();
+		if(!VhtQuest2(m_hubQuest).m_fFlameMask.m_result) {
+			s = s .. StringTable.localize("$VHT_QST_4_FireMask");
+		}
+		return s;
+	}
+}
 
 // quest 5: guardian of steel
 class VhtQuest5 : VhtQuest {}
@@ -144,12 +196,39 @@ class VhtQuestHolder : Inventory {
 	}
 	override void preTravelled() {
 		for(int i = 0, j = m_quests.size(); i < j; ++i) {
-			m_quests[i].vhtPreTravelled();
+			if(m_quests[i]) {
+				m_quests[i].vhtPreTravelled();
+			}
 		}
 	}
 	override void travelled() {
 		for(int i = 0, j = m_quests.size(); i < j; ++i) {
-			m_quests[i].vhtTravelled();
+			if(m_quests[i]) {
+				m_quests[i].vhtTravelled();
+			}
 		}
 	}
+	void vhtTick() {
+		for(int i = 0, j = m_quests.size(); i < j; ++i) {
+			if(m_quests[i]) {
+				m_quests[i].vhtTick();
+			}
+		}
+	}
+	string vhtDescribe() {
+		string s = "";
+		for(int i = 0, j = m_quests.size(); i < j; ++i) {
+			if(m_quests[i]) {
+				s.appendFormat(
+					"\cu- \cn%s\c-\n%s\n\n",
+					StringTable.localize(
+						m_quests[i].vhtLevelInfo().levelName,
+						false
+					),
+					m_quests[i].vhtDescribe()
+				);
+			}
+		}
+		return s;
+	}
 }
diff --git a/zscript.zsc b/zscript.zsc
index 7da235e..a92ab60 100644
--- a/zscript.zsc
+++ b/zscript.zsc
@@ -1,6 +1,6 @@
 version "4.8"
 
-#include "vhtzs/fnplayer.zsc"
+#include "vhtzs/fn.zsc"
 #include "vhtzs/fx.zsc"
 #include "vhtzs/projectiles.zsc"
 #include "vhtzs/weapons.zsc"