Macduff and Lennox have arrived at Macbeth's castle with the other thanes, and they wake Macbeth with their knocking. Macduff explains that they've come to meet with Duncan as he ordered them to, so Macbeth leads the men to the king's room. He pretends that he believes that the king is still sleeping. When Macduff goes to wake the king Lennox tells Macbeth about the ominous bird calls believed to prophecy death that kept them awake through the night. Macduff comes out of the king's room yelling that the king has been murdered. Macbeth, acting shocked, enraged, and heartbroken, follows Lennox into the slain king's room. Macduff shouts for alarm bells to be rung to wake the castle because the king has been killed.
Lady Macbeth, Malcolm, Donalbain, and Banquo come in and learn of Duncan's death. Lennox says that the guards appear to be the murderers because their clothes and swords were covered in blood. Lennox also notes that the guards appeared disoriented when they woke, as if they were delusional and dangerous. Macbeth tells them that he was so emotional over the king's death that he killed the guards without thinking. His love and his loyalty to Duncan precluded logic and reason.
Lady Macbeth faints and is helped away as the thanes decide to get dressed and then meet up again. Malcolm and Donalbain talk to each other when the thanes have gone. The king's sons are afraid that they are in danger because they are the heirs to the throne. For safety they decide that Malcolm will go to England and Donalbain to Ireland because they believe that the plot is not finished and they are the next targets. They sneak away from the castle before the thanes return.
