Middle aged couple, advertising designer Bruno an and his wife Madeleine, a housewife is a reasonably content Parisian couple until Bruno's director gets the idea that their ad campaigns need spicing up with eroticism. Then their relationship takes a turn toward the steamy because he gives him a stipend to investigate eroticism and chooses Madeleine as his assistant. They experiment with sexy games (e.g., Madeleine's telling Bruno that she isn't wearing underwear when they are out in public, having sex in their car beside the road, pretending to pick each other up in a shoe store, etc.) Then they are invited to go on holiday in the country with a couple more experienced in eroticism. Solange and Maurice are plotting a couple-swapping escapade. The sexy games amount to a couple of erotic "dare you" temptations and a visit to a local 24/7 orgy house. The games finally get too scary for her and she runs out followed by Bruno.