When Iranian-American Kamran Smith learns that his big brother, Darius, has been labelled a terrorist, he sets out to piece together the codes and clues that will save his brother's life and his country from a deadly terrorist attack.

A mysterious telegram sends Amy and Dan Cahill off to Russia, where they search for a treasure stolen by the Nazis, the truth about the end of the Romanov dynasty, and information about the death of their parents.

A clue takes Amy and Dan Cahill to Egypt, where they investigate the origins of the rivalry between the Tomas and Ekaterina branches of their family and try to figure out if they can trust a message from their dead grandmother Grace.

After delivering the last ransom, Amy and Dan discover that Vesper One has a terrifying plot and they race against time to stop him from harming millions of innocent people.

Dan and Amy Cahill are given the choice of receiving a million dollars or uncovering the thirty-nine clues hidden around the world that will lead to the source of the family's power, but by taking on the clues, they end up in a dangerous race against their own family.

Targeted by Interpol after a series of spectacular heists, a reluctant Amy and Dan are ordered by Vesper One to steal the world's largest diamond, a demand that is challenged by their efforts to rescue the Cahill hostages and stop a Vesper mole.

Returned by a surprising twist to their first mission on U.S. soil since the beginning of the Clue hunt, Amy and Dan discover evidence of a mole in their organization who proves to be one of their closest confidantes and who reveals, even more disturbingly, the true agenda of the Vespers.

During World War II, eleven-year-old Felicity is sent from London to Bottlebay, Maine, to live with her grandmother, aunt, uncle, and a reclusive boy who helps her decode mysterious letters that contain the truth about her missing parents.

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,...