diff --git a/titlecase/__init__.py b/titlecase/__init__.py
index fd24431..bdee4bb 100755
--- a/titlecase/__init__.py
+++ b/titlecase/__init__.py
@@ -123,10 +123,14 @@ def titlecase(text, callback=None, small_first_last=True, preserve_blank_lines=F
                     continue
 
             if APOS_SECOND.match(word):
+                # Everything past the second letter was shouted along with
+                # the rest of the line, so it needs the same downcasing the
+                # other branches below give their words before recapping.
+                rest = word[3:].lower() if all_caps else word[3:]
                 if len(word[0]) == 1 and word[0] not in 'aeiouAEIOU':
-                    word = word[0].lower() + word[1] + word[2].upper() + word[3:]
+                    word = word[0].lower() + word[1] + word[2].upper() + rest
                 else:
-                    word = word[0].upper() + word[1] + word[2].upper() + word[3:]
+                    word = word[0].upper() + word[1] + word[2].upper() + rest
                 tc_line.append(word)
                 continue
 
diff --git a/titlecase/tests.py b/titlecase/tests.py
index 9265ec0..c1745fd 100644
--- a/titlecase/tests.py
+++ b/titlecase/tests.py
@@ -246,6 +246,14 @@
         "O'GranGe",
         "O'GranGe",
     ),
+    (
+        "D'ARTAGNAN AND THE THREE MUSKETEERS",
+        "d'Artagnan and the Three Musketeers",
+    ),
+    (
+        "O'BRIEN'S HOUSE IS FOR SALE",
+        "O'Brien's House Is for Sale",
+    ),
     (
         "o'melveny/o'doyle o'Melveny/o'doyle O'melveny/o'doyle o'melveny/o'Doyle o'melveny/O'doyle",
         "O'Melveny/O'Doyle O'Melveny/O'Doyle O'Melveny/O'Doyle O'Melveny/O'Doyle O'Melveny/O'Doyle",