diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 75cd3c227..0f9104a80 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -7,6 +7,7 @@ class ApplicationController < ActionController::Base
   # For APIs, you may want to use :null_session instead.
   protect_from_forgery with: :exception
   helper :application
+  rescue_from GdsApi::HTTPNotFound, with: :error_not_found
 
 private
   def set_slimmer_headers
@@ -31,4 +32,7 @@ def finder_slug
     raise NotImplementedError
   end
 
+  def error_not_found
+    render status: :not_found, text: "404 error not found"
+  end
 end
diff --git a/app/controllers/email_alert_subscriptions_controller.rb b/app/controllers/email_alert_subscriptions_controller.rb
index eedf1df9f..2e2fd14d3 100644
--- a/app/controllers/email_alert_subscriptions_controller.rb
+++ b/app/controllers/email_alert_subscriptions_controller.rb
@@ -6,11 +6,7 @@ class EmailAlertSubscriptionsController < ApplicationController
   protect_from_forgery except: :create
 
   def new
-    if content
-      @signup = signup_presenter
-    else
-      error_not_found
-    end
+    @signup = signup_presenter
   end
 
   def create
@@ -34,7 +30,7 @@ def signup_presenter
   end
 
   def content
-    @content ||= content_store.content_item(request.path)
+    @content ||= content_store.content_item!(request.path)
   end
 
   def finder_slug
@@ -42,7 +38,7 @@ def finder_slug
   end
 
   def finder
-    FinderPresenter.new(content_store.content_item("/#{finder_slug}"))
+    FinderPresenter.new(content_store.content_item!("/#{finder_slug}"))
   end
 
   def finder_format
@@ -73,10 +69,4 @@ def email_signup_attributes
       "filter" => chosen_options,
     }
   end
-
-  def error_not_found
-    render status: :not_found, text: "404 error not found"
-  end
-
 end
-
diff --git a/app/controllers/finders_controller.rb b/app/controllers/finders_controller.rb
index 181962c85..85299bc99 100644
--- a/app/controllers/finders_controller.rb
+++ b/app/controllers/finders_controller.rb
@@ -17,7 +17,7 @@ def show
 private
   def finder
     @finder ||= FinderPresenter.new(
-      content_store.content_item("/#{finder_slug}"),
+      content_store.content_item!("/#{finder_slug}"),
       facet_params,
       keywords,
     )
diff --git a/docs/finder-content-item.md b/docs/finder-content-item.md
new file mode 100644
index 000000000..a0db6f983
--- /dev/null
+++ b/docs/finder-content-item.md
@@ -0,0 +1,61 @@
+# The Finder Content Item Format
+
+A Finder Content Item is a specialisation of the [Content Item](https://github.com/alphagov/content-store/blob/master/doc/content_item_fields.md). This guide explains what goes in the details hash of the ContentItem and why.
+
+The Finder Content Item is used by Finder Frontend to render the Finder page. Most of what it uses goes in the `details` hash.
+
+# The `details` hash
+
+## `beta`
+
+A boolean. Required.
+
+A flag used to decide if the Beta banner should be rendered.
+
+## `beta_message`
+
+A string. Optional. Can be set to `null`.
+
+Can contain HTML. If `beta` is true, `beta_message` will be passed to the beta banner.
+
+## `document_noun`
+
+A string. Required.
+
+The lowercase singular version of whatever format the Finder is using. For example: [`/cma-cases`](https://www.gov.uk/cma-cases) has a `document_noun` of `case`, [`/aaib-report`](https://www.gov.uk/aaib-reports) has a `document_noun` of `report`. This is used to construct the sentence descriving the current search by the user.
+
+## `document_type`
+
+A string. Required.
+
+[snake_case](http://en.wikipedia.org/wiki/Snake_case) string which tells Finder Frontend what doctype to limit the search to in Rummager. It must match the name of the file describing the doctype [in Rummager](https://github.com/alphagov/rummager/tree/master/config/schema/default/doctypes).
+
+## `email_signup_enabled`
+
+A boolean. Required.
+
+Used to decide if the link to the email alert signup page should be displayed
+
+## `format_name`
+
+A string. Optional.
+
+Not specifically used by the Finder, but used by [Specialist Frontend](https://github.com/alphagov/specialist-frontend) to link back to the Finder.
+Usually a singularised version of the title of the Finder - `"Competition and Markets Authority case"` for [`/cma-cases`](https://www.gov.uk/cma-cases) for example.
+However there are edge cases where it's not the same such as `"Medical safety alert"` for [Alerts and recalls for drugs and medical devices](https://www.gov.uk/drug-device-alerts).
+
+## `signup_link`
+
+A string. Optional.
+
+If `email_signup_enabled` is set to true, the link being displayed will point to `base_path/email-signup` where `base_path` is from the Finder object. `signup_link` allows you to point it at a different URL, [Drug Safety Update](https://www.gov.uk/drug-safety-update) and [Drug Device Alerts](https://www.gov.uk/drug-device-alerts) are the two which currently use this feature.
+
+## `show_summaries`
+
+A boolean. Required.
+
+Used to decide if the summaries for Documents should be displayed in the results list. It will truncate the summary at the end of the first sentence.
+
+## facets
+
+__TO DO__
diff --git a/spec/controllers/email_alert_subscriptions_controller_spec.rb b/spec/controllers/email_alert_subscriptions_controller_spec.rb
index 4a174261b..fc4a8e4a4 100644
--- a/spec/controllers/email_alert_subscriptions_controller_spec.rb
+++ b/spec/controllers/email_alert_subscriptions_controller_spec.rb
@@ -5,6 +5,17 @@
 
 describe EmailAlertSubscriptionsController do
 
+  describe 'GET #new' do
+    describe "finder email signup item doesn't exist" do
+      it 'returns a 404, rather than 5xx' do
+        content_store_does_not_have_item('/does-not-exist/email-signup')
+
+        get :new, slug: 'does-not-exist'
+        expect(response.status).to eq(404)
+      end
+    end
+  end
+
   describe 'POST "#create"' do
     let(:alert_name) { double(:alert_name) }
     let(:alert_identifier) { double(:alert_identifier) }
diff --git a/spec/controllers/finders_controller_spec.rb b/spec/controllers/finders_controller_spec.rb
new file mode 100644
index 000000000..9c2bbdcfa
--- /dev/null
+++ b/spec/controllers/finders_controller_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+require 'gds_api/test_helpers/content_store'
+include GdsApi::TestHelpers::ContentStore
+include FixturesHelper
+
+describe FindersController do
+  describe "GET show" do
+    describe "finder item doesn't exist" do
+      it 'returns a 404, rather than 5xx' do
+        content_store_does_not_have_item('/does-not-exist')
+
+        get :show, slug: 'does-not-exist'
+        expect(response.status).to eq(404)
+      end
+    end
+  end
+end