A bunch of teens head off, amid much surf guitar music, to a near deserted island. The owner of the island George (Brian Donlevy) doesn't want the island's secret discovered so he sends his daughter Junior (Jayne Mansfield) to see what is going on and get rid of the teens. What is the secret? Well that the island is where the fabled fountain of youth is located apparently. Junior is more interested in seeing her boyfriend Irving (Jack E Leonard) who lives on the island, though he is more interested in plants. Much inane antics and music (and a lot of dancing by scantily clad young people - being spied on by old men natch) take place...
So, this isn't a great film. It is light and cheaply made. So cheap in fact they ran out of money so didn't film the end of it. However, it isn't all bad (just mostly) - some of the music is in fact rather good.