diff --git a/evennia/utils/ansi.py b/evennia/utils/ansi.py
index a9f95b0c9c..3eaf5a0356 100644
--- a/evennia/utils/ansi.py
+++ b/evennia/utils/ansi.py
@@ -618,7 +618,7 @@ class ANSIString(unicode):
         code_indexes.extend(
             cls._shifter(second._code_indexes, len(first._raw_string)))
         char_indexes.extend(
-            cls._shifter(second._code_indexes, len(first._raw_string)))
+            cls._shifter(second._char_indexes, len(first._raw_string)))
         return ANSIString(raw_string, code_indexes=code_indexes,
                           char_indexes=char_indexes,
                           clean_string=clean_string)
@@ -660,7 +660,7 @@ class ANSIString(unicode):
         a start and end with [x:y], but many forget that they can also specify
         an interval with [x:y:z]. As a result, not only do we have to track
         the ANSI Escapes that have played before the start of the slice, we
-        must also replay any in these intervals, should the exist.
+        must also replay any in these intervals, should they exist.
 
         Thankfully, slicing the _char_indexes table gives us the actual
         indexes that need slicing in the raw string. We can check between
diff --git a/evennia/utils/tests.py b/evennia/utils/tests.py
index b75d813632..08886fbe94 100644
--- a/evennia/utils/tests.py
+++ b/evennia/utils/tests.py
@@ -135,6 +135,21 @@ class ANSIStringTestCase(TestCase):
         self.assertEqual(mxp1, ANSIString(mxp1))
         self.assertEqual(mxp2, unicode(ANSIString(mxp2)))
 
+    def test_add(self):
+        """
+        Verify concatination works correctly.
+        """
+        a = ANSIString("{gTest")
+        b = ANSIString("{cString{n")
+        c = a + b
+        result = u'\x1b[1m\x1b[32mTest\x1b[1m\x1b[36mString\x1b[0m'
+        self.checker(c, result, u'TestString')
+        char_table = [9, 10, 11, 12, 22, 23, 24, 25, 26, 27]
+        code_table = [
+            0, 1, 2, 3, 4, 5, 6, 7, 8, 13, 14, 15, 16, 17, 18, 19, 20, 21, 28, 29, 30, 31
+        ]
+        self.table_check(c, char_table, code_table)
+
 
 class TestIsIter(TestCase):
     def test_is_iter(self):