Camille and Madeleine along with their friends Marguerite and Sophie are waiting excitedly for their cousins to arrive for the Summer holidays. The children fill their days building cabins, having picnics and games of hide and seek but things nearly go wrong when Sophie, hiding in an hollowed out tree trunk but is unable to climb out.

But things really get exciting when Sophie's mother and cousin Paul unexpectedly return, it turns out they had escaped the shipwreck in which they were thought to have drowned and had made their way to a foreign land! The children are enthralled by the Crusoe-like tales of survival and adventure.