diff --git a/app/main/views/tour.py b/app/main/views/tour.py
index c17c51bf8..4a29a667a 100644
--- a/app/main/views/tour.py
+++ b/app/main/views/tour.py
@@ -49,6 +49,11 @@ def tour_step(service_id, template_id, step_index):
     if db_template['template_type'] != 'sms':
         abort(404)
 
+    if 'placeholders' not in session:
+        return redirect(url_for(
+            '.begin_tour', service_id=current_service.id, template_id=template_id
+        ))
+
     template = get_template(
         db_template,
         current_service,
@@ -119,6 +124,11 @@ def check_tour_notification(service_id, template_id):
         show_recipient=True,
     )
 
+    if 'placeholders' not in session:
+        return redirect(url_for(
+            '.begin_tour', service_id=current_service.id, template_id=template_id
+        ))
+
     placeholders = fields_to_fill_in(template, prefill_current_user=True)
 
     if not all_placeholders_in_session(template.placeholders):
diff --git a/tests/app/main/views/test_tour.py b/tests/app/main/views/test_tour.py
index 93ccd951d..9375593b4 100644
--- a/tests/app/main/views/test_tour.py
+++ b/tests/app/main/views/test_tour.py
@@ -234,6 +234,30 @@ def test_should_403_if_user_does_not_have_send_permissions_for_tour_step(
     )
 
 
+def test_tour_step_redirects_to_tour_start_if_placeholders_doesnt_exist_in_session(
+    client_request,
+    mock_get_service_template_with_multiple_placeholders,
+    service_one,
+    fake_uuid,
+):
+    with client_request.session_transaction() as session:
+        assert 'placeholders' not in session
+
+    client_request.get(
+        'main.tour_step',
+        service_id=SERVICE_ONE_ID,
+        template_id=fake_uuid,
+        step_index=1,
+        _expected_status=302,
+        _expected_redirect=url_for(
+            'main.begin_tour',
+            service_id=SERVICE_ONE_ID,
+            template_id=fake_uuid,
+            _external=True,
+        ),
+    )
+
+
 def test_back_link_from_first_get_tour_step_points_to_tour_start(
     client_request,
     mock_get_service_template_with_multiple_placeholders,
@@ -518,6 +542,30 @@ def test_back_link_from_check_tour_notification_points_to_last_tour_step(
     )
 
 
+def test_check_tour_notification_redirects_to_tour_start_if_placeholders_doesnt_exist_in_session(
+    client_request,
+    mock_get_service_template_with_multiple_placeholders,
+    service_one,
+    fake_uuid,
+):
+    with client_request.session_transaction() as session:
+        assert 'placeholders' not in session
+
+    client_request.get(
+        'main.check_tour_notification',
+        service_id=SERVICE_ONE_ID,
+        template_id=fake_uuid,
+        step_index=1,
+        _expected_status=302,
+        _expected_redirect=url_for(
+            'main.begin_tour',
+            service_id=SERVICE_ONE_ID,
+            template_id=fake_uuid,
+            _external=True,
+        ),
+    )
+
+
 def test_check_tour_notification_redirects_to_first_step_if_not_all_placeholders_in_session(
     client_request,
     mock_get_service_template_with_multiple_placeholders,