What would happen if you discovered that your family was one of the most powerful in human history? What if you were told that the source of the family's power was hidden around the world, in the form of 39 clues? What if you were given a choice - take a million dollars and walk away ... or get the first clue? If you're Amy and Dan Cahill, you take the clue - and begin a very dangerous race.

Where are Amy and Dan Cahill? The two kids were last seen in Egypt, hunting for one of the 39 Clues that could make them the most powerful people on earth. But no one has seen the siblings since. Has the ruthless Irina Spasky finally tracked them down? Or worse ... the Madrigals?

"Amy and Dan Cahill have been located once again, this time in the company of the notoriously unreliable Alistair Oh. Could they have been foolish enough to make an alliance? Spies report that Amy and Dan seem to be tracking the life of one of the most powerful fighters the world has ever known. If this fearsome warrior was a Cahill, his secrets are sure to be well-guarded . . . and the price to uncover them just might be lethal."--Publisher.

Throughout the hunt for the 39 Clues, Amy and Dan Cahill have uncovered history's greatest mysteries and their family's deadliest secrets. But are they ready to face the truth about the Cahills and the key to their unmatched power? After a whirlwind race that's taken them across five continents, Amy and Dan face the most the difficult challenge yet -- a task no Cahill dared to imagine. When faced with a choice that could change the future of the world,...

The most dangerous secret in Amy and Dan's past is unveiled in Book 7 of the #1 New York Times bestselling series. The hunt for 39 hidden Clues that lead to an unimaginable power have taken a heavy toll on fourteen-year-old Amy Cahill and her younger brother, Dan. They've just seen a woman die. They're wanted by the Indonesian police. They're trapped on an island with a man who knows too much about the death of their parents. And a tropical storm...

Cahills are being kidnapped by a shadowy group known only as the Vespers. Now Amy and Dan have only 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.

When the Vespers continue their abductions and cross a line by kidnapping Atticus, an 11-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...

The Cahill family have protected the secret of the powerful serum for generations. Amy and Dan continue to try to find it.

A strange telegram lures fourteen-year-old Amy Cahill and her younger brother, Dan, deep into Russia and away from the only trustworthy adult they know. Signed with the initials NRR, the telegram launches a race to uncover a treasure stolen by the Nazis and the truth about the murder of the last Russian royal family. All too soon, the treasure hunt starts to smell like a Lucian trap. But the bait might just be irresistible . . . what will Amy

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