David Pittu

Amy and Dan have managed to rescue one of the Cahills kidnapped by the Vespers, but the remaining hostages are still in peril. Their search for the next ransom item leads Amy and Dan to Turkey and then to Italy where a visit to the site of an ancient disaster changes everything. The Vespers are far more dangerous than the siblings ever imagined and, even worse, it looks like they have an undercover mole posing as a Cahill. Amy and Dan have to face

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

Defend the Clues

Fourteen-year-old Amy Cahill and her younger brother, Dan, thought they could return to their regular lives when they found the 39 Clues that safeguard their family's great power. But they were wrong. Powerful enemies—the Vespers—have been waiting in the shadows. And they'll stop at nothing to grab the Clues. Four powerhouse authors unite to expose the 500-year-old secret struggle between the Cahills and the Vespers. The

The blockbuster series continues with a Cahill family member from the past bent on revenge! Who is the Outcast and why is he threatening the lives of innocent people? Book 3 reveals a shocking secret that will send Amy and Dan—and the world—reeling.