Simple summary of 'Macbeth'?

In the play, Macbeth kills Duncan, the King of Scotland, with the help of his wife. Witches play a part in the play by foretelling that Macbeth will become king, but that Macbeth's friend Banquo will have sons who become kings. After he kills Banquo, Macbeth becomes king and tries to kill everyone who might want to take the throne away from him. The ghost of Banquo, whom he kills, haunts him at an important banquet. Because killing the king was wrong, Macbeth's wife dies and Macbeth is overthrown. Duncan's son Malcolm then becomes King of Scotland. The play has five acts. a href="http://simple.wikipedia.org/wiki/Macbeth" rel="nofollow"http://simple.wikipedia.org/wiki/Macbeth/a