In the prologue to Book IX, Milton says that his work must now take a tragic tone and that this Christian epic, though different, is nonetheless more heroic than earlier epics like the Iliad and the Aeneid. Again, he calls on Urania as the muse of Christian inspiration to help him complete his work and show the true heroism that lies in the Christian idea of sacrifice. Then Milton returns to his story.
Satan returns to Eden eight days after being forced out by Gabriel. He has studied all the animals and has decided to approach Eve in the form of a serpent which he considers to be the "subtlest Beast of all the Field" (86).
The following morning, Adam and Eve prepare for their daily work tending the Garden. Because the Garden's growth seems to surpass their labors, Eve suggests that on this day they work apart. She thinks they can accomplish more working individually. Adam argues the point with Eve, saying that Raphael has warned them of dangers and that she is more vulnerable by herself. He and she continue this argument — she proposing that they work alone; he proposing that they work together — until Adam finally relents; however, he makes Eve promise to return to their bower soon, but Milton comments that she will never return to Adam in the way that she was that morning.
