Three witches fortell that knight Macbeath will be promoted to "Thane of Cawdor" and then King of scotland.
KIng Duncan announces that Macbeth is promoted to "Thane of Cawdor". Knowing that the prophecy was true, Macbeth considered to kill King Duncan so he can be king.
Macbeath and Lady Macbeath team up to kill the king, and killed others as well. Macbeth was crowed king, but he and Lady Macbeth were extremly paranoid.
Meanwhile, Hectate, the later of the The Three Witches, scolded them helping a person like Macbeth, togeather the group of withes made a final prophecy against Macbeth. Hundreds of kilometers a way, Duncan's son Malcom was planning a rebellion against Macbeth with Macduff.