Breakaway [39 clues. Unstoppable Volume: bk. 2]by Hirsch, Jeff 

BTSB Prebound(Scholastic, 2014)

BTSB #: 446806 Available

Dewey: FAges: 8-12   
AR: 4.9 MG RC: 4.4 3-5

Genres: Adventure Fiction Mystery Fiction

Subjects: Mystery fiction Adventure fiction

Summary: 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 their enemy closing in Dan finds himself facing the one terror he never imagined--being betrayed by his own sister.

Flashpoint [39 clues. Unstoppable Volume: bk. 4]by Korman, Gordon 

BTSB Prebound(Scholastic, 2014)

BTSB #: 530049 Available

Dewey: FAges: 9-12   
AR: 5.8 MG RC: 5.2 3-5 Lexile: 790

Genres: Adventure Fiction Mystery Fiction

Subjects: Siblings - Fiction Adventure fiction

Summary: Fifteen-year-old Amy Cahill has only a few days to live. The antidote she needs for the poison inside her 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.