On a camping trip to Arizona with their grandfather, the Alden children search for a lost gold mine.

When their grandfather arranges for them to spend two week at Sunny Oaks, the four Alden children enjoy settling into the routines of farm life but become suspicious about a mysterious horse locked in the stables.

"Learning about paleontology and fossil hunting under renowned scientist Dr. Iris Prez while attending summer camp in Colorado, the Aldens investigate an outbreak of strange events that local superstition attributes to a bigfoot creature roaming the valley"--WorldCat.

When they help out at a guide dog training school, the Alden children meet several people who seem obsessed with a particular dog named Ginger.

Benny wants adventure and finds it as he and the other Alden children help uncover the plan of those who would prevent ballooning from coming to Lloyd's Landing.

The Aldens are excited to learn about beekeeping. But when equipment goes missing, they have more than honey to harvest -- they have a mystery to solve!

Can the Aldens figure out who's responsible for the bad press before the center gets shut down for good? Henry, Jessie, Violet, and Benny are excited to learn more about raptors when they volunteer at a rehab center for wild birds. But not long after they arrive, a series of strange events makes it seem like someone might be trying to sabotage the center. Who could the culprit be, and why would they want to cause trouble for injured birds?

The Alden children draw upon their resourcefulness to save the neighborhood firehouse from being torn down, while they also face a series of mysterious incidents connected with it.

"The winter sports season is here, and the Aldens are excited about all the snow activities--especially snowboarding. But soon they find themselves in the middle of a mystery surrounding a star athlete and a stolen snowboard"-- Provided by publisher.

"When the Alden siblings visit their grandfather's friend in an apartment building, they begin to wonder about the many mysterious events that keep happening on the thirteenth floor of that building."--