While working as counselors at a summer camp, twins Sara and Sam investigate the double mystery of food disappearing from a locked storeroom and strange occurrences in the wood.

While accompanying their father to Wyalusing, Pennsylvania, to do research on a French refugee settlement of 200 years ago, twins Sam and Sara become involved in a search for the valuable stolen pendant of an Indian princess.

While visiting Aunt Kay in Hawaii, twins Sara and Sam uncover a mystery surrounding an ancient curse.

Teen-agers searching for a treasure hidden at an old farm find a secret message written in code.

While visiting relatives in Florida, teenage twins Sara and Sam investigate a mystery on a nearby key, where strange incidents are occurring in a villa left abandoned by the death of a stage magician.

Teenage twins Sara and Sam investigate a young Vietnamese refugee hiding in an abandoned cabin and the mysterious disappearance of thoroughbred stallions from a neighbor's horse farm.

Ghost Town Mystery

by Ruth Nulton Moore

Published October 1999
Accompanying their father on a project that takes them to a ghost town in Nevada, teenage twins Sara and Sam discover peculiar nocturnal activities and clues to a hidden treasure of gold nuggets.