The 39 Clues: Cahills vs. Vespers Book 6: Day of Doom

Interest LevelReading LevelReading A-ZATOSWord Count
Grades 4 - 8Grade 5n/a4.554977
The Ultimate Sacrifice

It started with a kidnapping. A shadowy organization known only as the Vespers snatched seven members of the Cahill family and demanded a series of bizarre ransoms from around the world. Thirteen-year-old Dan Cahill and his older sister Amy began a global treasure hunt, determined to bring back whatever Vesper One needed, so long as it kept the hostages safe.

But when they deliver the last ransom, Amy and Dan discover Vesper One’s terrifying endgame. The objects he demanded are vital pieces in a Vesper plot that will harm millions of innocent people. Now the two siblings and their friends are in an all-out sprint to stop Vesper One . . . before the whole world goes BOOM.
Hardcover, 272 pages
Published on March 5, 2013 by Scholastic Inc.
ISBN-10: 054529844X
ISBN-13: 9780545298445
10 Book Reviews
  • 4usa
    4usaThursday, May 14, 2020 at 9:38 am55 stars
    This is the last book in an incredible series! Dan and Amy now know that they have been collecting these very specific items for a doomsday device and have some impossible decisions to make it they want to save their family and the world! It's a good thing Dan has been collecting the ingredients because they are going to need the serum! They also end up having an unexpected rescuer!
    • oofman
      oofmanThursday, January 31, 2019 at 10:17 am44 stars
      it is good because you never know what happens next. but it is also kind of scary so try it if your brave
      • goals
        goalsThursday, May 19, 2016 at 5:52 pm
        The series was good but this book kinda ruined it all. Why Evaaaaaaaaaaaaaaaaaaaaaaan
        • sharkbomb85
          sharkbomb85Sunday, May 8, 2016 at 11:53 am55 stars
          This book continues the battle between the Cahills and the Vespers, and it pops up some funny little scenes.
          • penguin313
            penguin313Wednesday, April 22, 2015 at 4:42 pm55 stars
            A good ending to the second 39 clues series. In this book, the Cahills fight their final battle against the Vespers, and find out the identities of their leaders.
            • deathknight
              deathknightWednesday, January 8, 2014 at 1:51 pm55 stars
              This book is the best book ever!! This book is the book with the most interests! Amy and Dan Cahill try to stop Vesper One's plan and save the world. Read this book for the shocking conclusion .
              • lollipopping
                lollipoppingFriday, October 18, 2013 at 10:34 pm11 star
                I read some reviews with solid information about it, and the book doesn't sound so interesting. I wouldn't want to read it. Too bad. It could have been better.
                • goals
                  goalsFriday, August 12, 2016 at 8:19 am
                  Yeah it was not that good. Too bad to end
                • singstar66
                  singstar66Sunday, October 6, 2013 at 1:14 pm55 stars
                  This is a good ending for the second series.
                  • miss_gold1
                    miss_gold1Saturday, September 28, 2013 at 11:48 pm55 stars
                    I'm reading this book now it's so good you can't stop reading it I wonder what happens in the end!!