diff --git a/plugin.rb b/plugin.rb
index fb63084..27b1fc1 100644
--- a/plugin.rb
+++ b/plugin.rb
@@ -8,3 +8,21 @@ enabled_site_setting :knowledge_explorer_enabled
 register_asset 'stylesheets/common/knowledge-explorer.scss'
 
 load File.expand_path('../lib/knowledge_explorer/engine.rb', __FILE__)
+
+after_initialize do
+  require_dependency 'search'
+
+  if SiteSetting.knowledge_explorer_enabled
+    if Search.respond_to? :advanced_filter
+      Search.advanced_filter(/in:kb/) do |posts|
+        selected_categories = SiteSetting.knowledge_explorer_categories.split("|")
+        categories = Category.where('slug IN (?)', selected_categories).pluck(:id)
+
+        selected_tags = SiteSetting.knowledge_explorer_tags.split("|")
+        tags = Tag.where('name IN (?)', selected_tags).pluck(:id)
+
+        posts.where('category_id IN (?) OR topics.id IN (SELECT DISTINCT(tt.topic_id) FROM topic_tags tt WHERE tt.tag_id IN (?))', categories, tags)
+      end
+    end
+  end
+end