The 39 Clues: Unstoppable Series is the third story arc in the bestselling young adult franchise The 39 Clues. It expands the story of Amy and Dan Cahill after the first two series The Clue Hunt and Cahills vs. Vespers. The series features 4 adventure books written by bestseller authors including Jude Watson and Gordon Korman.
Breakaway is a brilliant adventure novel and the 2nd book in bestselling young adult series, The 39 Clues: Unstoppable. Originally published in 2014, the book is written by Jeff Hirsch.