diff --git a/pelican/plugins/summary.py b/pelican/plugins/summary.py
index 0549ca7d..b32d59c5 100644
--- a/pelican/plugins/summary.py
+++ b/pelican/plugins/summary.py
@@ -19,17 +19,8 @@ def content_object_init(instance):
     if 'summary' in instance.metadata:
         return
 
-    try:
-        content = instance.content
-    except:
-        # in some tests, this fails because a context has not been set
-        return
-
-    # monkey patch a new function around get_content that removes summary
-    # markers
-    prev_get_content = instance.get_content
-    def get_content(self, siteurl):
-        content = prev_get_content(siteurl)
+    def _get_content(self):
+        content = self._content
         if self.settings['SUMMARY_BEGIN_MARKER']:
             content = content.replace(
                 self.settings['SUMMARY_BEGIN_MARKER'], '', 1)
@@ -37,23 +28,25 @@ def content_object_init(instance):
             content = content.replace(
                 self.settings['SUMMARY_END_MARKER'], '', 1)
         return content
-    instance.get_content = types.MethodType(get_content, instance)
-    
+    instance._get_content = types.MethodType(_get_content, instance)
+
     # extract out our summary
-    begin_summary = -1
-    end_summary = -1
-    if instance.settings['SUMMARY_BEGIN_MARKER']:
-        begin_summary = content.find(instance.settings['SUMMARY_BEGIN_MARKER'])
-    if instance.settings['SUMMARY_END_MARKER']:
-        end_summary = content.find(instance.settings['SUMMARY_END_MARKER'])
-    if begin_summary != -1 or end_summary != -1:
-        # the beginning position has to take into account the length
-        # of the marker
-        begin_summary = (begin_summary + 
-                         len(instance.settings['SUMMARY_BEGIN_MARKER'])
-                         if begin_summary != -1 else 0)
-        end_summary = end_summary if end_summary != -1 else None
-        instance._summary = content[begin_summary:end_summary]
+    if not hasattr(instance, '_summary'):
+        content = instance._content
+        begin_summary = -1
+        end_summary = -1
+        if instance.settings['SUMMARY_BEGIN_MARKER']:
+            begin_summary = content.find(instance.settings['SUMMARY_BEGIN_MARKER'])
+        if instance.settings['SUMMARY_END_MARKER']:
+            end_summary = content.find(instance.settings['SUMMARY_END_MARKER'])
+        if begin_summary != -1 or end_summary != -1:
+            # the beginning position has to take into account the length
+            # of the marker
+            begin_summary = (begin_summary +
+                            len(instance.settings['SUMMARY_BEGIN_MARKER'])
+                            if begin_summary != -1 else 0)
+            end_summary = end_summary if end_summary != -1 else None
+            instance._summary = content[begin_summary:end_summary]
 
 def register():
     signals.initialized.connect(initialized)