When a mysterious letter written in code arrives at King's house for his human, Kayla, he follows the trail of the person who left it.

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.

Sly uses her detective skills to help her friends solve mysteries that all involve some kind of code.

"Could the Mark Twain books hidden through Book Scavenger contain clues about the string of recent arson fires plaguing the city? And will Emily and James uncover the mystery before the arsonist comes after them?"--

When a new book arrives at the library with a secret code written inside, Derek, with the help of his friends, follows the clues from one novel to the next and makes a discovery that may help him get past a terrible loss.

Lucas's father has recently died in Afghanistan, and to help him cope, his grandmother sends him to Camp Kawani, a camp for kids who have lost a parent. While there, he hears about the local legend of Thomas Jefferson Beale. Beale supposedly hid a hoard of gold in the mountains 200 years before. The location is encrypted in a set of codes no one has ever been able to decipher. When Lucas and his newfound friends decide to track down the treasure,...

Vega Jane has never left the village of Wormwood. But this isn't unusual, nobody has ever left the village of Wormwood. At least not until Quentin Herms vanishes into the unknown. Vega knows Quentin didn't just leave, but that he was chased. And he's left behind a very dangerous trail of clues that only she can decode. The Quag is a dark forest filled with terrifying beasts and bloodthirsty Outliers. But just as deadly are the threats that exist within...

"¿Qué pasaría si descubrieras que tu familia es una de las más poderosas de toda del historia de la humanidad? ¿Y si te dijeran que la fuente de poder de la familia está escondida por todo el mundo en forma de 39 pistas? ¿Y si, además, te dieran a elegir entre tener un millón de dolares... o conseguir la primera de las pistas? Si fueras Amy y Dan Cahill, ¡escogerías la pista y emperazarías una carrera muy peligrosa!" --From publisher's...