diff --git a/render.py b/render.py
index cbf8828..16a8ac7 100644
--- a/render.py
+++ b/render.py
@@ -877,6 +877,7 @@ def shift_clips(data, offset):
     for clip in data:
         clip['in'] += offset
         clip['out'] += offset
+    return data
 
 def scene_subtitles(scene, options):
     import item.models
@@ -1076,7 +1077,9 @@ def join_subtitles(base_prefix, options):
     scenes = list(sorted(glob('%s/*/scene.json' % base_prefix)))
     data = []
     position = 0
-    for scene in scenes:
+    for scene_json in scenes:
+        with open(scene_json) as fd:
+            scene = json.load(fd)
         subs = scene_subtitles(scene, options)
         data += shift_clips(subs, position)
         position += get_scene_duration(scene)