I'm so sorry. (I hope the last one will go through after 24 hours..)
Make sure to prepare for the last Chapter.
If you have the food in storage and a Tomb ready for collecting and all of the materials ready for making the Tome Translation (and all of the materials for upgrading you Tomb to Level 10), the actual making of the 'Tome Translation' takes 6 hours after which you can immediately upgrade and finish the event.
So don't lose hope and be prepared. Good luck.