diff --git a/book/_toc.yml b/book/_toc.yml
index c536dd3a..1349810f 100644
--- a/book/_toc.yml
+++ b/book/_toc.yml
@@ -39,6 +39,6 @@ parts:
       - file: notebooks/4a_bound_long_wave
       - file: notebooks/4b_shallow_water_tides
 
-  - caption: Week 4
+  - caption: Week 5
     chapters:
       - file: notebooks/5_coastal_impact_beach_states