"It's time for the annual pet fair and the twins have been hard at work teaching their dog, Max, some new tricks. But on their way to the fairgrounds, they're offered not one, but two intriguing cases. Pets from the pet show have gone missing and their guardians are blaming each other for the disappearances. Meanwhile, Lark and Connor's frenemy, Sophie, thinks her house might be haunted and refuses to go inside. The twins split up to solve the mysteries,...

"Nico and his twin sister, Letta, are exhibiting a volcano at the school science fair--until the creepy scientist who has moved in next door suddenly appears and uses their experiment for her own purposes"--Title verso page.

The Code Busters are competing in their school's science fair, but when a mysterious drone ruins their project, it is up to sixth grader Cody and her friends to figure out who is responsible. Back matter includes keys to the codes and solutions to the coded messages that appear throughout the text.