You were a spy sent by Duke Leto Atreides to gather intel on the Baron of House Harkonnen, Vladimir Harkonnen. The Duke doubted that the Baron might be planning a scheme with the Emperor to abolish the rule of House Atreides over Arrakis.

The Duke's doubts were in place. The Baron was planning the downfall of House Atreides. He had conspired with the Emperor to kill every last one of the Atreides. Even the Duke's heir, Paul Atreides, would not be spared.

"There are no satellites over Arrakis. The Atreides will die in the dark, and no one will be spared! Not even the Duke's son!" You had to tell the Duke of the incoming surprise attack immediately. If you don't, the Harkonnens will reclaim Arrakis.