You might consider comparing and contrasting Lady Macbeth as she appeared in the first acts of the play with the way she appears in the sleepwalking scene at the end. At first she was full of self-confidence and assured her husband that their whole scheme would be so easy. At the end she is a physical and mental wreck. After committing the murder of Duncan, Macbeth told his wife he heard a voice cry, "Sleep no more!" She paid no attention to him. She said, "You do unbend your noble strength to think so brainsickly of things." Now, however, it appears that she is having trouble sleeping too. You might also include the commentary of the doctor and nurse who are watching her during her sleepwalking. You don't necessarily have to draw any moral at the end. It might be sufficient simply to describe her pathetic condition. Of course, I don't know what the rest of your essay is like. Generally a conclusion relates back to the introduction and the thesis statement.