The Landons are in the Caribbean, in Virgin Islands National Park, to figure out what is destroying the coral reefs and causing the hawksbill sea turtle to disappear. Jack and Ashley find themselves hopelessly entangled in the mysterious life of Forrest Winthrop IV, the adopted son of a U.S. diplomat. Why is he so anxious to save an island woman named Cimmaron? What secret do they share? Follow the action to Jumbie Bay and see what the full moon reveals.

The hawkshill sea turtle is disappearing from the waters of the Caribbean, and the Landon's are in Virgin Islands National Park to figure out why.

While she studies condors in the Grand Canyon a scientist's life is threatened, and the strange, hostile, teenage computer whiz in her family's foster care might be involved.

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.

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.

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

While lost in a tunnel at Carlsbad Cavern, thirteen-year-old Jack, eleven-year-old Ashley, and their eight-year-old foster brother, Sam, think bats and darkness are their worst problems, until they stumble across thieves.