Unstoppable is the series that follows the Cahills vs. Vespers series. It is the third arc in The 39 Clues. It has four books and no card packs.
This book is written by Jude Watson. It was released October 1, 2013.
The Cahill Family Has A Secret
For five hundred years, they have guarded the 39 Clues — thirty-nine ingredients in a serum that transforms whomever takes it into the most powerful person on earth. If the serum got into the wrong hands, the disaster would rock the world. So certain Cahills have always made it their mission to keep the serum safe, buried, locked away. Until now.
Thirteen-year-old Dan Cahill and his older sister, Amy, are the latest guardians of the Clues. They think they've done everything right, but a tiny mistake leads to catastrophe. The serum is missing and Dan and Amy have to get it back and stop who stole it . . . before it's game over. For everyone.
This book is written by Jeff Hirsch. It was released on January 28, 2014.
A Nightmare Come True As a member of the most powerful family history has ever known, thirteen-year-old Dan Cahill has been shot at, kidnapped, and even thrown into a pit with a deadly snake. He's survived it all due to luck, smarts, and his older sister, Amy, who always sticks by his side.
Now Dan and Amy are facing their greatest threat yet, an enemy who has found a way to use the source of the Cahill family power against them. To stop him, Dan and Amy must set out on a desperate mission that will take them from one of the world's hottest regions all the way to the frozen blast of the Arctic Circle. But with the enemy closing in , Dan finds himself facing the one terror he never imagined - being betrayed by his own sister
Book Three: Countdown
This book is written by Natalie Standiford. It was released on May 1, 2014.
The clock has finally run out for the Cahills. As the leaders of the world’s most powerful family, Dan and Amy have been in the crosshairs for too long. It was only a matter of time until luck failed them.
Media tycoon and presidential candidate J. Rutherford Pierce has set his sights on destroying the siblings. And after numerous close calls, it looks like he’s about to get his wish.
Now Dan is hopelessly trapped and nothing can save him. Nothing except unleashing an evil the Cahills have spent centuries trying to hide.
The Cahills have always had a secret weapon, but it comes at a great cost. With everything to lose, Amy has to ask herself the question that haunts her nightmares: Just how far is she willing to go to save her little brother?
Book Four: Flashpoint
The Unstoppable series finale is written by Gordon Korman.
FINAL HOURS Tick tock. Fifteen-year-old Amy Cahill only has few days to live. There’s a poison coursing through her, and her only chance is to collect ingredients for an antidote. Too bad the antidote ingredients are scattered around the world. And too bad that survival is by far Amy’s smallest problem.
The antidote she needs is also the only thing capable of stopping a deadly enemy. J. Rutherford Pierce is on the brink of becoming the most powerful man in the world, and if he does, no one will be safe. Amy and her younger brother, Dan, will do everything it takes to bring Pierce down. Even if Amy must pay the ultimate price.