diff --git a/app/controllers/lookups_controller.rb b/app/controllers/lookups_controller.rb
index a5dd82e4..66dbacd5 100644
--- a/app/controllers/lookups_controller.rb
+++ b/app/controllers/lookups_controller.rb
@@ -5,6 +5,10 @@ class LookupsController < ApplicationController
 
   def show
     @result = @key.lookup(@node)
+  rescue Hdm::Error => error
+    @error = error
+
+    render action: "error"
   end
 
   private
diff --git a/app/views/lookups/error.html.erb b/app/views/lookups/error.html.erb
new file mode 100644
index 00000000..9df4a8e7
--- /dev/null
+++ b/app/views/lookups/error.html.erb
@@ -0,0 +1,5 @@
+<%= turbo_frame_tag "lookup-result-frame" do %>
+  <p class="alert alert-danger">
+    <%= @error.message %>
+  </p>
+<% end %>
diff --git a/test/fixtures/files/puppet/environments/lookup_tests/data/common.yaml b/test/fixtures/files/puppet/environments/lookup_tests/data/common.yaml
index 636779ce..5f46d2d2 100644
--- a/test/fixtures/files/puppet/environments/lookup_tests/data/common.yaml
+++ b/test/fixtures/files/puppet/environments/lookup_tests/data/common.yaml
@@ -18,6 +18,7 @@ hdm_nested_hash:
   nested_hash:
     integer: 32
     added_by_common: common
+hdm_mixed_types: 42
 lookup_options:
   '^hdm_duplicates':
     merge: hash
@@ -26,4 +27,6 @@ lookup_options:
   hash_syntax:
     merge:
       strategy: deep
+  hdm_mixed_types:
+    merge: deep
 
diff --git a/test/fixtures/files/puppet/environments/lookup_tests/data/nodes/lookup.betadots.training.yaml b/test/fixtures/files/puppet/environments/lookup_tests/data/nodes/lookup.betadots.training.yaml
index af1d6d20..fefa500d 100644
--- a/test/fixtures/files/puppet/environments/lookup_tests/data/nodes/lookup.betadots.training.yaml
+++ b/test/fixtures/files/puppet/environments/lookup_tests/data/nodes/lookup.betadots.training.yaml
@@ -14,3 +14,5 @@ hdm_nested_hash:
   origin: node
   nested_hash:
     integer: 5
+hdm_mixed_types:
+  from_node: 23