Five kids and a dog investigate the disappearance of a professor, uncovering a conspiracy involving criminals related to his alternative energy project; they attempt to rescue him from kidnappers.

The Famous Five Julian, Dick, Anne, George and Timmy (the dog) spend their vacation together, while George's dad (Professor Quentin ) is staying on a nearby island where he works on a project which might bring forward new methods of using alternative energies. But one day, he disappears and the five friends are soon convinced that he was kidnapped. Determined to rescue Professor Quentin, they not only have to deal with thugs and gangsters, but also uncover a huge conspiracy.—Dimitris Kamitsis