The Medusa Plot (Cahills vs. Vespers Book One)

by Gordon Korman
Lexile:  730
Genre:  Mystery

Amy and Dan Cahill have survived the clue hunt and are looking forward to settling back into a regular old life with no globe trotting adventures.  This hope is shattered when at various world wide locations, people close to Amy and Dan are kidnapped at the same exact moment.  Amy and Dan have been warned by someone who calls himself Vesper One.  If they ever want to see their family members alive again, they must follow his instructions.  So Amy and Dan have no choice but to embark on a new adventure.