Junie and his elder sister Carmen have proved in their previous adventures that not only can they help their parents on their own but can also cope with cases worthy of real spies. At this time, not their parents, Gregorio and Ingrid, but Juni and Carmen will perform a new task. They go on a mysterious island, where one scientist and inventor creates supernatural beings. Juni and Carmen have to stop the mad villain, but they have competitors in this task- brother and sister Gary and Gerti. These two competing spyware duets have one goal - to find and destroy the device, which can cause irreparable damage worldwide. This job turns out to be too complex for the young spies whose parents and grandparents come to help them.