The play begins with the brief appearance of a trio of witches and then moves to a military camp, where the Scottish King Duncan hears the news that his generals, Macbeth and Banquo, have defeated two separate invading armies--one from Ireland, led by the rebel Macdonwald, and one from Norway.There, they show him a sequence of demons and spirits who present him with further prophecies: he must beware of Macduff, a Scottish nobleman who opposed Macbeth's accession to the throne; he is incapable of being harmed by any man born of woman; and he will be safe until Birnam Wood comes to Dunsinane Castle.The witches vanish, and Macbeth and Banquo treat their prophecies skeptically until some of King Duncan's men come to thank the two generals for their victories in battle and to tell Macbeth that he has indeed been named thane of Cawdor.She desires the kingship for him and wants him to murder Duncan in order to obtain it. When Macbeth arrives at Inverness, she overrides all of her husband's objections and persuades him to kill the king that very night.Fearful of the witches' prophecy that Banquo's heirs will seize the throne, Macbeth hires a group of murderers to kill Banquo and his son Fleance.The witches prophesy that Macbeth will be made thane (a rank of Scottish nobility) of Cawdor and eventually King of Scotland.Duncan's sons Malcolm and Donalbain flee to England and Ireland, respectively, fearing that whoever killed Duncan desires their demise as well.Lady Macbeth tries to neutralize the damage, but Macbeth's kingship incites increasing resistance from his nobles and subjects.They also prophesy that Macbeth's companion, Banquo, will beget a line of Scottish kings, although Banquo will never be king himself.Macbeth is intrigued by the possibility that the remainder of the witches' prophecy--that he will be crowned king--might be true, but he is uncertain what to expect.Prince Malcolm, Duncan's son, has succeeded in raising an army in England, and Macduff joins him as he rides to Scotland to challenge Macbeth's forces.The invasion has the support of the Scottish nobles, who are appalled and frightened by Macbeth's tyrannical and murderous behavior.Nevertheless, he awaits the English and fortifies Dunsinane, to which he seems to have withdrawn in order to defend himself, certain that the witches' prophecies guarantee his invincibility.He is struck numb with fear, however, when he learns that the English army is advancing on Dunsinane shielded with boughs cut from Birnam Wood.The previous thane betrayed Scotland by fighting for the Norwegians and Duncan has condemned him to death.At the feast that night, Banquo's ghost visits Macbeth.