Shatterproof (The 39 Clues: Cahills vs. Vespers, Book 4)

The fourth book in the CAHILLS VS. VESPERS series, the follow up to the worldwide bestseller THE 39 CLUES.

After pulling some spectacular heists, Amy and Dan have become two of Interpol's most wanted criminals. So when Vesper One orders them to steal the world's largest diamond, they know they're facing life in prison . . . or worse. But with the Cahill hostages still in peril, Amy and Dan have no choice but to launch a mission that leads them to an ancient city full of dangerous secrets. With a Vesper mole sabotaging the Madrigals from inside, Amy and Dan have to fulfill their enemy's request before it's too late. Vesper One has developed a taste for killing Cahills, and Amy and Dan aren't going to wait to see who's next.

Roland Smith first worked with animals at the Oregon Zoo, and he has been involved in animal rescues and conservation work around the world for more than 20 years. He is the author of numerous books for young readers, including Jack's Run, Zach's Lie, Peak, the Cryptid Hunters series, and the Storm Runners series. He is also the coauthor of numerous picture books with his wife, Marie. Roland lives with Marie on a farm south of Portland, Oregon. You can find him online at rolandsmith.com.