In 1825, in Amsterdam, Messieurs Balthazar and Cornelius sit down to supper during a particularly strong thunderstorm. Balthazar informs Cornelius that he is aware that Cornelius is in love with Christiane, who had been raised by Balthazar’s mother, and is practically his sister. He gives his blessing to a marriage between Cornelius and Christiane. Sara Vanderven arrives, and Cornelius informs her that Balthazar has been in love with her for years, but is too intimidated to let her know. Sara agrees to marry Balthazar, if he will bring to her home a certain locket, which contains a flower that had meant something to them when they were children. However, when Bathazar goes to his study to retrieve the locket, he is shocked to find that the room had been burgled, and all of his valuables taken, including the locket.