Robert and Françoise Monier make a hot air balloon to fly to the stratosphere. After a visit to Venus, they return home, but have only aged 15 days whereas 25 years have passed on Earth.

Commander Gerard and his band of guerrillas have found the ideal hideout: a nursing home in the Alps where, along with the mentally ill, are also hiding a Jewish girl and a Swiss doctor who might be a spy for the Germans ...

A retelling of Tristan and Isolde set in 1940s France.