In this scene, the knight is in love with another knights wife. The two talk every night and the lady comes out of bed to talk to this other knight. Quote: "...Talking thence with her loving friend, on the other side. they'd often send love gifts flying through the air, ...nothings missing from their pleasure"
In the second scene, the husband is concerned that she is cheating on him and gets jealous. This makes the woman upset and angry at her husband. Quote: "...Longed to set eyes upon the other. They have their hope and their refuge: no-one detected their subterfuge, no-one could tell her not to stare, out her window--and he'd be there..."
In the third scene, the woman has told her husband that the reason she gets up at night is to see hear the nightingale sing its beautiful song. The husband sends his servant to get the bird and kills the bird while he has a fit.
The wife then tells the servant to bring the dead bird to the castle of the knight. To tell the knight that the love between them will die because she will not be able to see him nor talk to him.
The knight gets the bird and the message and is upset by the outcome of their love. Quote: "...The knight who had listened to every word, was sad as could be at how things had turned out. No vile churl he, though, no lazy lout..."
The knight, in memory of the lady has the bird covered in precious metals and stones and then carries the bird around for all eternity.