"Cahills are being kidnapped by a shadowy group known only as the Vespers. Now Amy and Dan have just days to fulfill a bizarre ransom request or their captured friends will start dying. Amy and Dan don't know what the Vespers want or how to stop them. Only one thing is clear: the Vespers are playing to win, and if they get their hands on the Clues the world will be their next hostage"--P. [4] of cover.

When the Vespers continue their abductions and cross a line by kidnapping Atticus, an eleven-year-old non-Cahill civilian and Dan's only friend, Dan and Amy confront their biggest challenge ever in order to keep Atticus alive.

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...