diff --git a/http-html.go b/http-html.go
index 3ef7ea4..ae6ddbe 100644
--- a/http-html.go
+++ b/http-html.go
@@ -182,7 +182,9 @@ func (r *HTWriter) WriteTo(w io.Writer) (int64, error) {
 		}
 		subject := ""
 		if s := twt.Subject(); s != nil {
-			subject = s.Tag().Text()
+			if tag := s.Tag(); tag != nil {
+				subject = tag.Text()
+			}
 		}
 		i, err = fmt.Fprintf(w, `
 			<article>