diff --git a/src/Query/GroupOption.php b/src/Query/GroupOption.php
index 5afb03e..a5030ee 100644
--- a/src/Query/GroupOption.php
+++ b/src/Query/GroupOption.php
@@ -106,18 +106,15 @@ class GroupOption implements QueryOptionInterface, QueryOptionTreeItemInterface
   /**
    * {@inheritdoc}
    */
-  public function apply($query, $original_query = NULL) {
-    if (is_null($original_query)) {
-      $original_query = $query;
-    }
+  public function apply($query, $parent_group = NULL) {
     switch ($this->conjunction) {
       case 'OR':
-        $group = $original_query->orConditionGroup();
+        $group = $query->orConditionGroup();
         break;
 
       case 'AND':
       default:
-        $group = $original_query->andConditionGroup();
+        $group = $query->andConditionGroup();
         break;
     }
 
@@ -128,12 +125,18 @@ class GroupOption implements QueryOptionInterface, QueryOptionTreeItemInterface
     }
 
     if (!empty($this->childGroups)) {
-      $group = array_reduce($this->childGroups, function ($group, $child) use ($original_query) {
-        return $child->apply($group, $original_query);
+      $group = array_reduce($this->childGroups, function ($group, $child) use ($query) {
+        return $child->apply($query, $group);
       }, $group);
     }
 
-    return $query->condition($group);
+    // We are at the beginning of the tree and there is no parent group.
+    if (is_null($parent_group)) {
+      return $query->condition($group);
+    }
+    else {
+      return $parent_group->condition($group);
+    }
   }
 
   /**