Christina, Grant, Mimi, and Papa head to the Great Smoky Mountains and end up in an A+ Appalachian mystery complete with an eerie mountain haze, spectacular scenery, a boisterous bear, confounding clues, and mystifying folklore!

Mimi, Papa, Christina, and Grant make an emergency landing on Diamond Shoals off the North Carolina coast and encounter a mysterious light on the beach.

Christina, Grant, Mimi, and Papa make their way to Mount Rushmore to check out the colossal carving of four presidents...and find a mountain's worth of mystery, history, precocious prairie dogs, quirky clues, befuddling Badlands, and one Crazy Horse!

Siblings Grant and Christina travel to the Hawaiian Islands with their grandparents, Mimi and Papa, where they learn about the history of Hawaii, but as they explore volcanoes and beaches, they uncover a mystery.

It's Girl Scout cookie sale time! The girls even get a chance to tour a new bakery where cookies are made. But when they see a mysterious mix-up at the cookie factory, and notice some of their cookie boxes are missing ... and get caught in a dark delivery truck, a mystery really starts cooking. Who is the cookie thief, anyway? And why?

Nick and Curie accompany their dad on an investigation into a forest fire in Yellowstone National Park.

Mimi, Papa, Grant, and Christina become embroiled in a mystery in Egypt that involves a missing pyramid.

Mimi, Papa, Cristina, and Grant find a series of clues that helps them to discover where a stolen statue from the Louvre Museum in Paris might be hidden.

"Christina, Grant, Mimi and Papa snowmobile into Yellowstone National Park to encounter mud pots, geysers, bison, beauty, bears, volcanic action, and a mystery of historic proportions!"--p. [4] of cover.

Michele, Michael, Jo Dee, and Brian set off on an adventure in North Carolina's pirate haunt port town of Bath, where they try to recover a special prop and save an outdoor drama while learning about the Golden Age of piracy.