Darrac, a reporter for Paris-Inter, and Nicole, a journalist for Le Soir-Express, know each other, compete and end up falling in love over the three police investigations they follow for their newspapers.
Taking advantage of their uncle's absence, André and Raymond Rafet organize a New Year's Eve party at his house. The uncle returns unexpectedly, disturbs the party, threatens his nephews to disinherit them and then locks himself in his office. A few minutes later, he is found dead, poisoned.
