Dr. Yueh is exposed before his betrayal as Jessica was trained as a truthsayer (as she remained loyal to the Bene Gesserit by giving birth to Ariste[2]), allowing Duke Leto Atredies and his house to survive.[1]
To protect spice production on Arrakis, the Emperor deploys his Sardaukar[1]
Arrakis erupts into a war of assassins.[1] This war is sectioned by the Emperor as long as the war remains contained. However, spice must flow.[3]
The Fremen are missing, presumed exterminated by Imperial propaganda and unreliable narrator[1][4][5]