What happens
Eleanor, the Duchess of Gloucester, summons a witch and conjurer to raise spirits and divine her future. Through magical ceremony, a spirit prophecies that a duke will depose Henry but outlive him violently; Suffolk will die by water; Somerset should avoid castles. York and Buckingham burst in, arrest the conspirators, and expose Eleanor's treachery. Hume, their spy, reveals he was hired by Suffolk and the Cardinal to trap Eleanor and undermine Gloucester.
Why it matters
This scene crystallizes the play's obsession with knowledge, destiny, and the unreliability of language itself. The witches' prophecies are presented as spectacle—thunder, spirits, riddling speech—yet they prove troublingly accurate, even as their meaning remains opaque. When the spirit says the duke who depos Henry will 'outlive' him and die violently, ambiguity becomes power; no one can act on a prophecy they cannot interpret. Eleanor's hunger for certainty about her future—Will Humphrey be king?—traps her instead. The scene suggests that the desire to know and control the future through language (written prophecy, magical summons) is itself a form of hubris that guarantees failure. Eleanor seeks to write her destiny and ends up written out of power.
More immediately, the scene exposes how thoroughly Eleanor is a pawn in a larger game. Hume's final soliloquy reveals that Suffolk and the Cardinal have orchestrated her fall from the beginning—they hired him to encourage her witchcraft so they could expose it and disgrace Humphrey. Eleanor's ambition, which seemed her own, was always a tool in others' hands. This structural irony mirrors the play's larger theme: characters believe they are plotting and controlling events, but they are themselves being plotted against by shadowy conspirators. The scene demonstrates that in this world, attempting to seize power through secrecy and magic only makes you more vulnerable to exposure and manipulation by those already in power.