Nearly two years ago, Meg Kenyon's father left their home in France to fight for the allies in World War II. Recently, Meg heard he had been taken prisoner by the Nazis. All Meg has left of him now are the codes he placed in a jar for her to decipher, an affectionate game the two of them once shared. But even those are running low. But the codes are running low, and soon there'll be nothing left of Papa for Meg to hold on to at all. Suddenly, an impossible...

Jax and Ethan must decode an ancient Greek cipher to uncover the location of two magical urns before the urns are used to remove all faith and love from the world.

Chronicles the first Vesper attack on Jan van Eyck's altarpiece at Ghent in the 1600s, then jumps to WWII and young Grace Cahill's desperate bid to save the masterwork from the Nazis.

While preparing for a fund-raiser antique show, Trixie and the other members of the Bob-Whites discover a secret code in the pages of an old magazine in the attic.

Ruby Redfort is a genius code-cracker, a daring detective, and a gadget-laden special agent who just happens to be a 13-year-old girl. She and her slick side-kick butler, Hitch, foil crimes and get into loads of scrapes with evil villains, but they're always ice-cool in a crisis.

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 Clue found in Book 3 sends Amy and Dan jetting off to find out just what's behind the fierce rivalry between the Tomas and Ekaterina branches of the Cahill family. Was a Clue stolen from the Tomas branch? Where is it now? And most important, can Amy and Dan get their hands on it before their rivals do?

Twins Josh and Danny continue following clues leading them to marbles filled with scientific code, despite the fact that mad scientist Petty Potts' REPTOSWITCH formula is having some very strange side-effects.

Ivy Seidel dreams of becoming a writer, a great American novelist. But running low on money and concerned that her writing might lack a depth and darkness, she takes a job teaching creative writing -- at a maximum-security prison. It is a world she has never experienced before, one ruled by enigmatic codes of honor, ceaseless aggression and absolutely savage violence. But one of the prisoners there is unlike any of the others, and unlike any man she...

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....