Amy and Dan are in a race for their lives . . . and the enemy may be even closer than they think. When seven members of their family were kidnapped by a sinister organization known as the Vespers, thirteen-year-old Dan Cahill and his older sister, Amy, vowed they'd stop at nothing to bring the hostages home. But then the ransom comes in and the Vespers demand the impossible. Amy and Dan have just days to track down and steal an ancient map. The only...

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.

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....