diff --git a/app.py b/app.py
index ce7e779..21f07dc 100644
--- a/app.py
+++ b/app.py
@@ -94,7 +94,7 @@ class Reaction(db.Model):
 
 def choose_new_next(min_like_num=10):
     for story in Story.query.filter_by(is_tree=False).all():
-        last_paragraph_id = Story.tail
+        last_paragraph_id = story.tail
         next_one = Paragraph.query.filter_by(parent_id=last_paragraph_id, is_hidden=False)\
                                   .order_by(Paragraph.like_num.desc()).first()
         if next_one and next_one.like_num >= min_like_num:
diff --git a/init_data.py b/init_data.py
index 31d889f..a812390 100644
--- a/init_data.py
+++ b/init_data.py
@@ -57,7 +57,7 @@ BEGIN_WORDS = [
 ]
 
 for idx, (title, text, avatar) in zip(range(1, 11), BEGIN_WORDS):
-    s = Story(id=idx, title=title, text=text, tail=idx,
+    s = Story(id=idx, title=title, text=text, tail=idx, is_tree=(idx == 10),
               avatar="/ordinary/static/img/" + avatar)
     p = Paragraph(id=idx, text=text, story_id=idx, is_chosen=True,
                   author="初始设定")