Die Walküre
Sieglinde lets Siegmund into the house and gives him a drink of mead.  They start to fall in love.  Hunding arrives and asks Siegmund who he is.  Siegmund says that his name ought to be Woeful because he has had an unhappy life.  When he was small he came home once and found his house burned down, his mother murdered and his twin sister had been abducted (taken away).  He then remembers that some years later he went to help a young lady who had been forced to marry a cruel man.  He had killed some of the man’s friends.  Hunding realizes that he himself was this man, so that he is Siegmund’s enemy.  He says to Siegmund that he can sleep in his house tonight because this is a law of hospitality, but in the morning he will have to fight him.