Geronimo investigates to see if the famous painting Mona Mousa holds a secret code.

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.

Unable to return to their normal lives despite the end of the Clue hunt, new Madrigal leaders Amy and Dan anxiously prepare for a retaliatory strike by the Vespers, who kidnap a number of Cahill family members and demand that Amy and Dan steal a famous painting.

"Discusses different methods of secret communications used by spies, such as Morse code, the Enigma machine, the Najavo language, and digital steganography, and includes career information"--

When a rare coin and a strange code are uncovered in McKenna School, Malcolm and the other classroom pets of the Midnight Academy take on their most challenging assignment yet and, through their investigations, they just might save the school from closing.

As Cruz and his friends continue to search for the third piece of the cipher, a mysterious message arrives suggesting that someone close to him is working for Nebula, leaving Cruz unsure of who he can trust.

"1940. Facing a seemingly endless war, fifteen-year-old Louisa Adair wants to fight back, make a difference, do something?anything to escape the Blitz and the ghosts of her parents, who were killed by enemy actions. But when she accepts a position caring for an elderly German woman in the small village of Windyedge, Scotland, it hardly seems like a meaningful contribution. Still, the war feels closer than ever in Windyedge, where Ellen McEwen, a volunteer...

"In 1994, four teenagers find a mysterious game at a yard sale. As they play it, they discover it is strangely connected to their lives. What will they risk to unravel the secrets of The initiative?"--Box.