diff --git a/lib/foundation/local.dart b/lib/foundation/local.dart
index be0efe0..c5f00b6 100644
--- a/lib/foundation/local.dart
+++ b/lib/foundation/local.dart
@@ -422,12 +422,30 @@ class LocalManager with ChangeNotifier {
     return files.map((e) => "file://${e.path}").toList();
   }
 
-  bool isDownloaded(String id, ComicType type, [int? ep]) {
+  bool isDownloaded(String id, ComicType type,
+      [int? ep, ComicChapters? chapters]) {
     var comic = find(id, type);
     if (comic == null) return false;
     if (comic.chapters == null || ep == null) return true;
+    if (chapters != null) {
+      if (comic.chapters?.length != chapters.length) {
+        // update
+        add(LocalComic(
+          id: comic.id,
+          title: comic.title,
+          subtitle: comic.subtitle,
+          tags: comic.tags,
+          directory: comic.directory,
+          chapters: chapters,
+          cover: comic.cover,
+          comicType: comic.comicType,
+          downloadedChapters: comic.downloadedChapters,
+          createdAt: comic.createdAt,
+        ));
+      }
+    }
     return comic.downloadedChapters
-        .contains(comic.chapters!.ids.elementAt(ep - 1));
+        .contains((chapters ?? comic.chapters)!.ids.elementAtOrNull(ep - 1));
   }
 
   List<DownloadTask> downloadingTasks = [];
diff --git a/lib/pages/local_comics_page.dart b/lib/pages/local_comics_page.dart
index 409ed1f..2b45c63 100644
--- a/lib/pages/local_comics_page.dart
+++ b/lib/pages/local_comics_page.dart
@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:venera/components/components.dart';
 import 'package:venera/foundation/app.dart';
 import 'package:venera/foundation/appdata.dart';
+import 'package:venera/foundation/comic_type.dart';
 import 'package:venera/foundation/local.dart';
 import 'package:venera/foundation/log.dart';
 import 'package:venera/pages/comic_details_page/comic_page.dart';
@@ -304,7 +305,9 @@ class _LocalComicsPageState extends State<LocalComicsPage> {
                   }
                 });
               } else {
-                (c as LocalComic).read();
+                // prevent dirty data
+                var comic = LocalManager().find(c.id, ComicType(c.sourceKey.hashCode))!;
+                comic.read();
               }
             },
             menuBuilder: (c) {
diff --git a/lib/pages/reader/images.dart b/lib/pages/reader/images.dart
index 43932c4..00018f1 100644
--- a/lib/pages/reader/images.dart
+++ b/lib/pages/reader/images.dart
@@ -26,7 +26,7 @@ class _ReaderImagesState extends State<_ReaderImages> {
     inProgress = true;
     if (reader.type == ComicType.local ||
         (LocalManager()
-            .isDownloaded(reader.cid, reader.type, reader.chapter))) {
+            .isDownloaded(reader.cid, reader.type, reader.chapter, reader.widget.chapters))) {
       try {
         var images = await LocalManager()
             .getImages(reader.cid, reader.type, reader.chapter);
diff --git a/lib/pages/reader/reader.dart b/lib/pages/reader/reader.dart
index 057e78b..cb75c04 100644
--- a/lib/pages/reader/reader.dart
+++ b/lib/pages/reader/reader.dart
@@ -115,7 +115,7 @@ class _ReaderState extends State<Reader>
 
   String get cid => widget.cid;
 
-  String get eid => widget.chapters?.ids.elementAt(chapter - 1) ?? '0';
+  String get eid => widget.chapters?.ids.elementAtOrNull(chapter - 1) ?? '0';
 
   List<String>? images;