* Cavern of Soul - Fixed a bug that caused that every spell could not be countered that was cast using the first (colorless) mana ability (fixes #391).

Mage.Sets/src/mage/sets/avacynrestored/CavernOfSouls.java

@@ -130,6 +130,7 @@ class CavernOfSoulsManaBuilder extends ConditionalManaBuilder {
 
     @Override
     public ConditionalMana build(Object... options) {
+        this.mana.setFlag(true); // indicates that the mana is from second ability
         return new CavernOfSoulsConditionalMana(this.mana);
     }
 
@@ -169,7 +170,7 @@ class CavernOfSoulsManaCondition extends CreatureCastManaCondition {
 
 class CavernOfSoulsWatcher extends WatcherImpl<CavernOfSoulsWatcher> {
 
-    public List<UUID> spells = new ArrayList<UUID>();
+    public List<UUID> spells = new ArrayList<>();
 
     public CavernOfSoulsWatcher() {
         super("ManaPaidFromCavernOfSoulsWatcher", WatcherScope.GAME);
@@ -188,7 +189,7 @@ class CavernOfSoulsWatcher extends WatcherImpl<CavernOfSoulsWatcher> {
     public void watch(GameEvent event, Game game) {
         if (event.getType() == GameEvent.EventType.MANA_PAYED) {
             MageObject object = game.getObject(event.getSourceId());
-            if (object != null && object.getName().equals("Cavern of Souls")) {
+            if (object != null && object.getName().equals("Cavern of Souls") && event.getFlag()) {
                 spells.add(event.getTargetId());
             }
         }

Mage.Tests/src/test/java/org/mage/test/cards/single/avr/CavernOfSoulsTest.java

@@ -82,7 +82,7 @@ public class CavernOfSoulsTest extends CardTestPlayerBase {
     }
 
     /**
-     * Tests card can be countered for cast with Cavern of Souls
+     * Tests spell can't be countered for cast with Cavern of Souls
      */
     @Test
     public void testDrakeCantBeCountered() {
@@ -90,6 +90,7 @@ public class CavernOfSoulsTest extends CardTestPlayerBase {
         addCard(Zone.HAND, playerA, "Cavern of Souls");
         addCard(Zone.HAND, playerA, "Azure Drake");
 
+        // {1}{U} Remove Soul - Counter target creature spell.
         addCard(Zone.HAND, playerB, "Remove Soul");
         addCard(Zone.BATTLEFIELD, playerB, "Island", 2);
 
@@ -107,5 +108,32 @@ public class CavernOfSoulsTest extends CardTestPlayerBase {
         assertGraveyardCount(playerA, "Azure Drake", 0);
         assertPermanentCount(playerA, "Azure Drake", 1);
     }
+    /**
+     * Tests spell can be countered if cast with colorless mana from Cavern
+     */
+    @Test
+    public void testDrakeCanBeCountered() {
+        addCard(Zone.BATTLEFIELD, playerA, "Mountain", 2);
+        addCard(Zone.BATTLEFIELD, playerA, "Island", 1);
+        addCard(Zone.HAND, playerA, "Cavern of Souls");
+        addCard(Zone.HAND, playerA, "Azure Drake");
 
+        // {1}{U} Remove Soul - Counter target creature spell.
+        addCard(Zone.HAND, playerB, "Remove Soul");
+        addCard(Zone.BATTLEFIELD, playerB, "Island", 2);
+
+        setChoice(playerA, "Drake");
+
+        playLand(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Cavern of Souls");
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Azure Drake");
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerB, "Remove Soul");
+
+        setStopAt(1, PhaseStep.BEGIN_COMBAT);
+        execute();
+
+        // check it was countered
+        assertGraveyardCount(playerB, "Remove Soul", 1);
+        assertGraveyardCount(playerA, "Azure Drake", 1);
+        assertPermanentCount(playerA, "Azure Drake", 0);
+    }
 }

Mage/src/mage/players/ManaPool.java

@@ -327,7 +327,7 @@ public class ManaPool implements Serializable {
         for (ConditionalMana mana : getConditionalMana()) {
             if (mana.get(manaType) > 0 && mana.apply(ability, game, mana.getManaProducerId())) {
                 mana.set(manaType, mana.get(manaType) - 1);
-                game.fireEvent(new GameEvent(GameEvent.EventType.MANA_PAYED, ability.getId(), mana.getManaProducerId(), ability.getControllerId()));
+                game.fireEvent(new GameEvent(GameEvent.EventType.MANA_PAYED, ability.getId(), mana.getManaProducerId(), ability.getControllerId(), 0, mana.getFlag()));
                 break;
             }
         }

Mage/src/mage/players/ManaPoolItem.java

@@ -66,6 +66,7 @@ public class ManaPoolItem implements Serializable {
         this.conditionalMana = conditionalMana;
         this.sourceId = sourceId;
         this.conditionalMana.setManaProducerId(sourceId);
+        this.flag = conditionalMana.getFlag();
     }
 
     public ManaPoolItem(final ManaPoolItem item) {