In "The Three Investigators and The Secret of Skeleton Island" the cult detective trio from Rocky Beach, California, fall into a breath-taking mixture of adventure, thriller and mystery. Only by a hairs-breadth did they escape with their lives after the successful completion of their last case.

A new case for the cult detectives! Not by coincidence, a mysterious videotape falls into the hands of Jupiter Jones, Pete Crenshaw and Bob Andrews during Jupiter's birthday party in Rocky Beach. On it is a recording of Jupiter's long dead parents. In their message they want to communicate to their son the key to an especially tricky riddle.