Prudence and Bélisaire Beresford have decided to take things easy. But when a rich Russian heiress disappears, Prudence can't resist and Bélisaire is forced onto the adventure. Their investigation will put them on the trail of a mysterious scientist who holds the secret to eternal youth...
Prudence Beresford
Bélisaire Beresford
Doctor Nicolas Roscoff
Doctor Matarazzi
Marie Van Dinh
Doctor Jünger
The General
The family doctor
Marie-Christine
Rudi
Prudence's father
Hector
Miss Sakhaline
The Countess
Gisèle
The receptionist
A policeman
The nude model
