Mysteries in our national parks

While at St. John National Park in the Virgin Islands for a seminar on coral reefs, the Landons help a wealthy thirteen-year-old to find his birth mother, who he believes is in danger.

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.

While their parents study why wolverines are disappearing from Alaska's Denali National Park, Jack and Ashley are stranded in a remote area with their mysterious new foster brother when a hit man's bullet triggers an avalanche.

While visiting the Everglades National Park with their parents, the Landon children uncover the mystery of dying manatees and learn important lessons about the natural environment.

Twelve-year-old Jack, his younger sister, and the family's teenage foster child Troy go to Yellowstone National Park, where Jack's mother, a wildlife veterinarian, is investigating the report that wolves reintroduced to the park have killed a dog there.

Jack, Ashley, and their parents visit Hawaii where they meet a Vietnamese boy who is going to live with his American grandfather whom he has never met, and are pursued by the Goddess Pele.