After failing his architect course, Simon, unemployed, lives with his friend, Carmen. Along with their roommate, Freddy the swindler, Carmen tricks him into believing that his architectural plans have been stolen by a wealthy contractor named Vincent Porel. Simon goes to him to demand an explanation. But he's thrown out by the businessman, who, moments later, accidentally hits him with his car and kills him.
At the same moment, Chrystèle, Vincent's wife, gives birth to a son, in which Simon is reincarnated. The newborn baby makes life impossible for Vincent, whom he sees as the person responsible for his misfortunes. Meanwhile, when Carmen finds out she is pregnant, Freddy pushes her to go to Porel and tell him that Simon is the father so she can get a hefty settlement from him.