The central conflict arises from Satan's defiance of God following his expulsion from Heaven and his subsequent attempt to corrupt humanity. The protagonist, Satan, seeks to establish a new kingdom in Hell and orchestrates a plan to undermine God's creation. He faces the logical constraints of his fallen state and the omnipotence of his adversary, while the narrative framework utilizes epic blank verse to detail the internal and external motivations of the fallen angels. This section of the work establishes the foundational stakes for the remainder of the epic poem.

Discussion often centers on the rhetorical brilliance of Satan's speeches and the moral ambiguity inherent in his characterization. Readers frequently highlight the density of Milton's language, which requires careful attention to grasp the nuances of his theological arguments. Critics often examine how the text reflects the political and religious tensions of the seventeenth century. The balance between the poem's grand scale and its intimate psychological insights remains a primary focus for scholars and students alike.