The theme of madness ties into this act in many ways. First of all, they still all think Prince Hamlet is insane because of his recent behavior. Secondly, Hamlet has just killed Ophelia's father and now she has seemed to go mad. Her father is now dead and her brother is gone to Paris and Hamlet, the man that she loved, is now also gone. The stress of all this happening to her at once drove her mad. Now Ophelia can do nothing but sing silly songs and prance around the palace. And by the end of the act Ophelia's madness has caused her fall into a stream and drown.