And this isn't a miniseries. That's got to go or at least not be spelled out. All we need to know is the Harkonnens hated Atriedes, the Emperor considered them a threat, so they got killed. Paul escapes, gets chummy with Fremen, makes Fremen army, he wins big time.The problem is that it's politics and power that's at the core of the story - the fear of losing his power that saw Shadam IV determined to take down House Atriedes, the old feud that made the Harkonnens his willing pawns, the policital power the Baron thought he'd gain, the political manipluations of the Bene Gesserit as part of their goal of the Kwisatz Hederach,
Also Paul is the Chosen One, Jedi, Spider-Man, Kwisatz Haderach, you know the drill. Next reel.