Thirteen-year-old Dan Cahill and his older sister Amy race against time to find an ancient map that has not been seen for half a century and use it to redeem their family members who have been kidnapped by a sinister organization called the Vespers.

The third book in the CAHILLS VS. VESPERS series, the follow up to the worldwide bestseller THE 39 CLUES. The Vespers have crossed a line. Amy and Dan were devastated when the Vespers kidnapped seven Cahills around the world, holding them hostage until Amy and Dan delivered an impossible ransom. But at least the hostages were Cahills - members of the world's most powerful family, trained to face all odds. Now the Vespers have gone too far. They've...

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...

When seven members of their family were kidnapped, thirteen-year-old Dan Cahill and his older sister, Amy, got ready for the fight of their lives. But their enemy, a terrifying group known as the Vespers, remained frustratingly elusive. They stay in the shadows, picking off Cahills one by one.And now the Vespers have landed their most serious blow yet - a blow that strikes at the very heart of the Cahill family. Because Amy and Dan discover that there's...

It started with a kidnapping. A shadowy organization known only as the Vespers snatched seven members of the Cahill family and demanded a series of bizarre ransoms from around the world. Thirteen-year-old Dan Cahill and his older sister Amy began a global treasure hunt, determined to bring back whatever Vesper One needed, so long as it kept the hostages safe. But when they deliver the last ransom, Amy and Dan discover Vesper One's terrifying endgame....