diff --git a/app/logical/post_sets/post.rb b/app/logical/post_sets/post.rb
index 30d76717e..79585110b 100644
--- a/app/logical/post_sets/post.rb
+++ b/app/logical/post_sets/post.rb
@@ -24,9 +24,8 @@ module PostSets
     end
 
     def wiki_page
-      return nil unless tag.present? && tag.wiki_page.present?
-      return nil unless !tag.wiki_page.is_deleted?
-      tag.wiki_page
+      return nil unless normalized_query.has_single_tag?
+      @wiki_page ||= WikiPage.undeleted.find_by(title: normalized_query.tags.first.name)
     end
 
     def tag
diff --git a/test/functional/posts_controller_test.rb b/test/functional/posts_controller_test.rb
index 173798edd..41bdc1c88 100644
--- a/test/functional/posts_controller_test.rb
+++ b/test/functional/posts_controller_test.rb
@@ -96,6 +96,13 @@ class PostsControllerTest < ActionDispatch::IntegrationTest
           assert_response :success
         end
 
+        should "show the wiki excerpt for a wiki page without a tag" do
+          as(@user) { create(:wiki_page, title: "no_tag") }
+          get posts_path(tags: "no_tag")
+          assert_select "#show-excerpt-link", count: 1
+          assert_select "#excerpt", count: 1
+        end
+
         should "show a notice for a single tag search with a pending BUR" do
           create(:bulk_update_request, script: "create alias foo -> bar")
           get_auth posts_path(tags: "foo"), @user