Dune Dissection Chapter Two

Dune Chapter 2 To attempt an understanding of Muad'Dib without understanding his mortal enemies, the Harkonnens, is to attempt to see the Truth without knowing Falsehood. It is the attempt to see the Light without Knowing Darkness. It cannot be.
~ from "Manual of Muad'Dib" by the Princess Irulan

In the second chapter, we meet the Enemy.

A hugely overweight man and

Quote: dark-haired youth of about sixteen years, round of face and with sullen eyes

along with

Quote: a slender, short man with an effeminate face

are looking at a high tech globe of tthe planet Arrakis. We soon learn that the big man is the Baron Vladimir Harkonnen, the youth is named Feyd-Rautha Harkonne, the Baron's heir, and the short guy is named Piter, who is identified as a mentat assassin.

They are discussing the Emperor giving Arrakis to the Atreides. We learn that the Baron has offered a peace meeting to Leto Atriedes and been refused. It soon becomes clear that somehow the Baron has manipulated things so that the Emperor ordered the Atreides to exchange Caladan for Arrakis, and that this is some sort of revenge plot upon the Duke by the Baron. The Harkonnen have an agent named Dr. Yueh who will soon bring the Atreides to their doom. When asked why not just have Yueh kill Leto right now, the Baron says it must be done on a larger scale, so that all of the Great Houses and the Atreides will know that he has brought the Atreides down.

The mentat reminds the Baron that he was promised the Lady Jessica as his reward for his part in the plans. The mentat and the Baron bicker like an old married couple, then the Baron has the mentat describe the big plan to Feyd.

In a few days the Atreides will be moving to Arrakis. It is thought that they will live in Arrakeen, as that city is most defensible. They believe that the Atreides will move into the Residency, previously home to Count Fenring (the Imperial Ambassador) and his Lady. The house has already been booby trapped for assassination attempts upon Paul. The Harkonnen agent is Dr. Yueh, but he has a special conditioning thought to be unbreakable. The Harkonnens have indeed broken it, but no one will ever suspect him as he has the Imperial Conditioning. They will make it look like Lady Jessica should be suspected instead. They will also have some uprisings in garrison towns to add to the stress and confusion. As soon as the Duke finally starts feeling secure, they will signal Yueh, and he will betray the Duke just as the planet is secretly invaded by Imperial Sardaukar (Imperial troopers).

Because House Harkonnen is doing the dirty work of the Imperium, they will be given back Arrakis, as well as a directorship in something called CHOAM, which will make them wealthy beyond dreams.

They will have it all -- wealth, power, a dirty secret (the Sardaukar involvement) to hold against the Emperor, and the public credit for the desctruction of their great enemies -- the Atreides.