 Harriet and Frank Allard have been married for many years. Almost twenty years ago, Harriet had a love affair with a colleague of Frank s, Claes von Klitzow, who made her pregnant. She had a son, Christer, whom Frank thinks that he is the father of. One day, Christer reveals that he is going to marry von Klitzow s daughter Louise. Harriet becomes upset but what will she do? Try to stop the marriage by telling the truth - which would endanger her marriage with Frank - or keep silent, which would mean that two siblings married?