The Milewskis are a middle-aged couple. Witold and Magda, both occupied with careers in managerial positions, create a solid, well-matched relationship. They have no children - this is Magda's decision, who preferred to pursue a career rather than take care of diapers. However, little remains of the bond they had at the beginning. Each Sunday, each of them cheats on their partner, and they both know nothing about it. Everything changes when Witold's younger brother Franek, a handsome geologist, shows up at their place.
The young couple love each other. The boy is in constant work which will fit him, and in the end becomes a petty thief who cannot pay his debts anymore and decides to steal from homes where he pays scheduled visits to lonely housewifes. The girl works a nurse but is too sensitive in extreme cases. Running parallel to their story is a metaphor involving a castaway on a junkyard, who tries every means possible to get rid of the dog which becomes attached to him. In the end he attaches sticks of dynamite to the dog, but he breaks loose and the explosion wipes them both.
