Little rat at the Opera de Paris , Delphine ( Delphine Desyeux ) is ecstatic. At twelve, she has been chosen to play the role of Galatea in the next ballet prepares the Palais Garnier . One evening, a small group of dancers , defying prohibitions, ventures into the roof of the Opera . But jealousy, one of the girls closed the door locked, preventing Delphine back ...This great adventure aired for the first time in 1966 on television was written by Odette Joyeux , from his own experience little rat when she was not an actress. By the famous cinematographer Philippe Agostini , the series goes behind the scenes of the ruthless world of dance . The adorable Delphine Desyeux , which will star opposite Jacques Brel in 1967 in the unforgettable" The Hazards of the trade" , is surrounded by Odette Joyeux , Louis Velle , Pierre Mondy , Françoise Rosay but also real dancers of the Opera in their own roles.