Given how ridiculously pointless it would be to attempt a plot summary of the the thriling Dune: Part Two, here's an entertaining sample from Wikipedia's attempt to do so: "Baron Vladimir Harkonnen replaces his nephew, Glossu Rabban, as Arrakis's ruler with his more cunning yet psychotic younger nephew, Feyd-Rautha. Lady Margot Fenring, a Bene Gesserit, is sent to evaluate Feyd-Rautha as a prospective Kwisatz Haderach and secure his genetic lineage." There, now you know.