Twelve-year-old Jack and his younger sister visit Mesa Verde National Park, where they delve into the park's history while gradually uncovering the mysterious past of their family's teenage foster child Lucky.

The Landon family makes a trip to Death Valley National Park accompanied by a mysterious new foster child, fourteen-year-old Leesa Sherman.

Visiting Zion National Park with his family, twelve-year-old Jack encounters two mysteries, the strange behavior of a band of wild mustangs and the possibly sinister actions of his new foster brother, a Shoshone boy.

"Bailey Johnson's sixteenth summer isn't going well. Three murders in one week is overkill--especially when she's the one who keeps finding the bodies. She just wants to be a normal teen with a fun summer job: mail jumping on the Lake Geneva Mailboat. But Detective Monica Steele and Officer Ryan Brandt are catching glimpses of a far bigger plot than anyone realized. A shadow is growing over the idyllic summer town, and the killings are far from over....