diff --git a/src/error.rs b/src/error.rs
index 1e6d641..0fd4925 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -18,6 +18,7 @@ pub(crate) enum Error {
     LogBuilder(log4rs::config::Errors),
     Parse(std::num::ParseIntError),
     Serial(serde_json::Error),
+    GitNoMaster,
 }
 
 impl fmt::Display for Error {
@@ -32,6 +33,7 @@ impl fmt::Display for Error {
             Error::LogBuilder(e) => write!(fmt, "LogBuilder({})", e),
             Error::Parse(e) => write!(fmt, "Parse({})", e),
             Error::Serial(e) => write!(fmt, "Serial({})", e),
+            Error::GitNoMaster => write!(fmt, "Repo doesn't have master branch"),
         }
     }
 }
@@ -39,10 +41,20 @@ impl fmt::Display for Error {
 impl ResponseError for Error {
     fn error_response(&self) -> HttpResponse {
         let mut buf = Vec::new();
-        templates::p500(&mut buf, VERSION_INFO, REPO_COUNT.load(Ordering::Relaxed)).unwrap();
-        HttpResponse::InternalServerError()
-            .content_type("text/html")
-            .body(buf)
+        match self {
+            Error::GitNoMaster => {
+                templates::p404_no_master(&mut buf, VERSION_INFO, REPO_COUNT.load(Ordering::Relaxed)).unwrap();
+                HttpResponse::NotFound()
+                    .content_type("text/html")
+                    .body(buf)
+            },
+            _ => {
+                templates::p500(&mut buf, VERSION_INFO, REPO_COUNT.load(Ordering::Relaxed)).unwrap();
+                HttpResponse::InternalServerError()
+                    .content_type("text/html")
+                    .body(buf)
+            }
+        }
     }
 }
 
diff --git a/src/main.rs b/src/main.rs
index 620377d..bd69145 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -75,7 +75,12 @@ fn hoc(repo: &str, repo_dir: &str, cache_dir: &str) -> Result<(u64, String, u64)
     let cache_dir = format!("{}/{}.json", cache_dir, repo);
     let cache_dir = Path::new(&cache_dir);
     let repo = Repository::open_bare(&repo_dir)?;
-    let head = format!("{}", repo.head()?.target().ok_or(Error::Internal)?);
+    // TODO: do better...
+    let head = match repo.head() {
+        Ok(v) => v,
+        Err(_) => return Err(Error::GitNoMaster),
+    };
+    let head = format!("{}", head.target().ok_or(Error::Internal)?);
     let mut arg_commit_count = vec!["rev-list".to_string(), "--count".to_string()];
     let mut arg = vec![
         "log".to_string(),
diff --git a/templates/p404_no_master.rs.html b/templates/p404_no_master.rs.html
new file mode 100644
index 0000000..dd49d8a
--- /dev/null
+++ b/templates/p404_no_master.rs.html
@@ -0,0 +1,16 @@
+@use super::base;
+@use crate::statics::VersionInfo;
+
+@(version_info: VersionInfo, repo_count: usize)
+
+@:base("Master Branch not Found - Hits-of-Code Badges", "404 - Master Branch not Found", {
+<p>
+<big>Sorry</big>. I couldn't find the master branch of your repositroy.
+Currently this service depends on the existence of a master branch. Please go
+<a href="/">back to the homepage</a>.
+</p>
+
+<p>
+If you think, this is a mistake on my side, please <a href="mailto:mail+hoc@@vbrandl.net">drop me a mail</a>.
+</p>
+}, version_info, repo_count)