diff --git a/src/pyj/read_book/iframe.pyj b/src/pyj/read_book/iframe.pyj
index 29f85b712a..d40fe152f4 100644
--- a/src/pyj/read_book/iframe.pyj
+++ b/src/pyj/read_book/iframe.pyj
@@ -21,7 +21,7 @@ from read_book.paged_mode import (
     onwheel as paged_onwheel, onkeydown as paged_onkeydown, scroll_to_elem,
     jump_to_cfi as paged_jump_to_cfi, handle_gesture as paged_handle_gesture,
     scroll_by_page as paged_scroll_by_page, anchor_funcs as paged_anchor_funcs,
-    snap_to_selection
+    snap_to_selection, reset_paged_mode_globals
 )
 from read_book.settings import apply_settings, opts
 from read_book.touch import create_handlers as create_touch_handlers
@@ -112,6 +112,7 @@ class IframeBoss:
         self.book = current_book.book = data.book
         spine = self.book.manifest.spine
         index = spine.indexOf(data.name)
+        reset_paged_mode_globals()
         set_layout_mode('flow' if FORCE_FLOW_MODE else data.settings.read_mode)
         if current_layout_mode() is 'flow':
             self.do_layout = flow_layout
diff --git a/src/pyj/read_book/paged_mode.pyj b/src/pyj/read_book/paged_mode.pyj
index 0f70d8c3dd..db58d9ce44 100644
--- a/src/pyj/read_book/paged_mode.pyj
+++ b/src/pyj/read_book/paged_mode.pyj
@@ -52,6 +52,11 @@ def in_paged_mode():
 col_width = screen_width = screen_height = cols_per_screen = gap = col_and_gap = 0
 is_full_screen_layout = False
 
+def reset_paged_mode_globals():
+    nonlocal _in_paged_mode, col_width, col_and_gap, screen_height, gap, screen_width, is_full_screen_layout, cols_per_screen
+    col_width = screen_width = screen_height = cols_per_screen = gap = col_and_gap = 0
+    is_full_screen_layout = _in_paged_mode = False
+
 def column_at(xpos):
     # Return the (zero-based) number of the column that contains xpos
     sw = document.body.scrollWidth