Answer:
Banquo and Fleance are riding their horses. The murderers are coming to kill them. They kill Banquo and he is yelling for his son to flee. Once the murderer puts out his torch Fleance is able to escape. The murderers take Banquo's body to show Macbeth.
Step-by-step explanation:
Macbeth has already met with the witches. People are dying and the prophecy is beginning to come true. Macbeth thinks he must kill Banquo and Fleance so that the other part of the prophecy does not come true. The witches' prophecy is now coming true - Fleance escapes and can now carry on his lineage.