diff --git a/resources/celerity/map.php b/resources/celerity/map.php
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -81,7 +81,7 @@
     'rsrc/css/application/owners/owners-path-editor.css' => '2f00933b',
     'rsrc/css/application/paste/paste.css' => '1898e534',
     'rsrc/css/application/people/people-profile.css' => '2473d929',
-    'rsrc/css/application/phame/phame.css' => '737792d6',
+    'rsrc/css/application/phame/phame.css' => '7448a969',
     'rsrc/css/application/pholio/pholio-edit.css' => 'b15fec4a',
     'rsrc/css/application/pholio/pholio-inline-comments.css' => '8e545e49',
     'rsrc/css/application/pholio/pholio.css' => 'ca89d380',
@@ -806,7 +806,7 @@
     'phabricator-uiexample-reactor-sendclass' => '1def2711',
     'phabricator-uiexample-reactor-sendproperties' => 'b1f0ccee',
     'phabricator-zindex-css' => '5b6fcf3f',
-    'phame-css' => '737792d6',
+    'phame-css' => '7448a969',
     'pholio-css' => 'ca89d380',
     'pholio-edit-css' => 'b15fec4a',
     'pholio-inline-comments-css' => '8e545e49',
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -3708,7 +3708,9 @@
     'PhabricatorXHProfSample' => 'applications/xhprof/storage/PhabricatorXHProfSample.php',
     'PhabricatorXHProfSampleListController' => 'applications/xhprof/controller/PhabricatorXHProfSampleListController.php',
     'PhabricatorYoutubeRemarkupRule' => 'infrastructure/markup/rule/PhabricatorYoutubeRemarkupRule.php',
+    'Phame404Response' => 'applications/phame/site/Phame404Response.php',
     'PhameBlog' => 'applications/phame/storage/PhameBlog.php',
+    'PhameBlog404Controller' => 'applications/phame/controller/blog/PhameBlog404Controller.php',
     'PhameBlogArchiveController' => 'applications/phame/controller/blog/PhameBlogArchiveController.php',
     'PhameBlogController' => 'applications/phame/controller/blog/PhameBlogController.php',
     'PhameBlogCreateCapability' => 'applications/phame/capability/PhameBlogCreateCapability.php',
@@ -8508,6 +8510,7 @@
     'PhabricatorXHProfSample' => 'PhabricatorXHProfDAO',
     'PhabricatorXHProfSampleListController' => 'PhabricatorXHProfController',
     'PhabricatorYoutubeRemarkupRule' => 'PhutilRemarkupRule',
+    'Phame404Response' => 'AphrontHTMLResponse',
     'PhameBlog' => array(
       'PhameDAO',
       'PhabricatorPolicyInterface',
@@ -8519,6 +8522,7 @@
       'PhabricatorApplicationTransactionInterface',
       'PhabricatorConduitResultInterface',
     ),
+    'PhameBlog404Controller' => 'PhameLiveController',
     'PhameBlogArchiveController' => 'PhameBlogController',
     'PhameBlogController' => 'PhameController',
     'PhameBlogCreateCapability' => 'PhabricatorPolicyCapability',
diff --git a/src/applications/phame/application/PhabricatorPhameApplication.php b/src/applications/phame/application/PhabricatorPhameApplication.php
--- a/src/applications/phame/application/PhabricatorPhameApplication.php
+++ b/src/applications/phame/application/PhabricatorPhameApplication.php
@@ -93,7 +93,9 @@
       '/' => array(
         '' => 'PhameBlogViewController',
         'post/(?P<id>\d+)/(?:(?P<slug>[^/]+)/)?' => 'PhamePostViewController',
+        '.*' => 'PhameBlog404Controller',
       ),
+
     );
   }
 
diff --git a/src/applications/phame/controller/PhameLiveController.php b/src/applications/phame/controller/PhameLiveController.php
--- a/src/applications/phame/controller/PhameLiveController.php
+++ b/src/applications/phame/controller/PhameLiveController.php
@@ -70,6 +70,8 @@
 
       $blog = $blog_query->executeOne();
       if (!$blog) {
+        $this->isExternal = $is_external;
+        $this->isLive = $is_live;
         return new Aphront404Response();
       }
 
@@ -81,6 +83,9 @@
       $blog = null;
     }
 
+    $this->isExternal = $is_external;
+    $this->isLive = $is_live;
+
     if ($post_id) {
       $post_query = id(new PhamePostQuery())
         ->setViewer($viewer)
@@ -109,8 +114,6 @@
       $post = null;
     }
 
-    $this->isExternal = $is_external;
-    $this->isLive = $is_live;
     $this->blog = $blog;
     $this->post = $post;
 
@@ -188,4 +191,30 @@
     return $crumbs;
   }
 
+  public function willSendResponse(AphrontResponse $response) {
+    if ($this->getIsExternal()) {
+      if ($response instanceof Aphront404Response) {
+        $page = $this->newPage()
+          ->setCrumbs($this->buildApplicationCrumbs());
+
+        $response = id(new Phame404Response())
+          ->setPage($page);
+      }
+    }
+
+    return parent::willSendResponse($response);
+  }
+
+  public function newPage() {
+    $page = parent::newPage();
+
+    if ($this->getIsLive()) {
+      $page
+        ->setShowChrome(false)
+        ->setShowFooter(false);
+    }
+
+    return $page;
+  }
+
 }
diff --git a/src/applications/phame/controller/blog/PhameBlog404Controller.php b/src/applications/phame/controller/blog/PhameBlog404Controller.php
new file mode 100644
--- /dev/null
+++ b/src/applications/phame/controller/blog/PhameBlog404Controller.php
@@ -0,0 +1,14 @@
+<?php
+
+final class PhameBlog404Controller extends PhameLiveController {
+
+  public function handleRequest(AphrontRequest $request) {
+    $response = $this->setupLiveEnvironment();
+    if ($response) {
+      return $response;
+    }
+
+    return new Aphront404Response();
+  }
+
+}
diff --git a/src/applications/phame/controller/blog/PhameBlogViewController.php b/src/applications/phame/controller/blog/PhameBlogViewController.php
--- a/src/applications/phame/controller/blog/PhameBlogViewController.php
+++ b/src/applications/phame/controller/blog/PhameBlogViewController.php
@@ -108,12 +108,6 @@
           $about,
       ));
 
-    if ($is_live) {
-      $page
-        ->setShowChrome(false)
-        ->setShowFooter(false);
-    }
-
     return $page;
   }
 
diff --git a/src/applications/phame/site/Phame404Response.php b/src/applications/phame/site/Phame404Response.php
new file mode 100644
--- /dev/null
+++ b/src/applications/phame/site/Phame404Response.php
@@ -0,0 +1,43 @@
+<?php
+
+final class Phame404Response extends AphrontHTMLResponse {
+
+  private $page;
+
+  public function setPage(AphrontPageView $page) {
+    $this->page = $page;
+    return $this;
+  }
+
+  public function getPage() {
+    return $this->page;
+  }
+
+  public function getHTTPResponseCode() {
+    return 404;
+  }
+
+  public function buildResponseString() {
+    require_celerity_resource('phame-css');
+
+    $not_found = phutil_tag(
+      'div',
+      array(
+        'class' => 'phame-404',
+      ),
+      array(
+        phutil_tag('strong', array(), pht('404 Not Found')),
+        phutil_tag('br'),
+        pht('Wherever you go, there you are.'),
+        phutil_tag('br'),
+        pht('But the page you seek is elsewhere.'),
+      ));
+
+    $page = $this->getPage()
+      ->setTitle(pht('404 Not Found'))
+      ->appendChild($not_found);
+
+    return $page->render();
+  }
+
+}
diff --git a/webroot/rsrc/css/application/phame/phame.css b/webroot/rsrc/css/application/phame/phame.css
--- a/webroot/rsrc/css/application/phame/phame.css
+++ b/webroot/rsrc/css/application/phame/phame.css
@@ -243,3 +243,13 @@
   left: 50px;
   position: absolute;
 }
+
+.phame-404 {
+  margin: 48px auto;
+  padding: 12px 24px;
+  border-radius: 6px;
+  min-width: 240px;
+  width: 50%;
+  color: {$darkgreytext};
+  background: {$greybackground};
+}