From the pubishers homepage:
It's Getting Dark
The Horizon Corporation is everywhere. They’re in the trids you watch, the music you listen to, and the news you consume. They’re propping up hundreds of major brands of products across the planet with their public relations skill. And they’re spending countless hours studying how you—that’s right, you—think so that they can lead your mind like a master leads a spaniel.
Denizens of the Sixth World have long suspected that there is a dark side to Horizon, if only because the corporation seemed too good to be true. If there is a dark side, it seems likely to come out soon, as the corporation has been under tremendous pressure recently—technomancers are plotting against it, spirits are causing problems in the Mojave, and Aztechnology is on the offensive, intent on keeping the competition down. That pressure is going to result in an explosion somewhere, and when it does, Horizon and the Sixth World will be changed forever.
The Twilight Horizon is a campaign book involving shadowrunners in the inner workings of Horizon and the troubles surrounding the corporation. Everything is leading to a crisis, and the runners will need to use all their skills to come out alive on the other side. Filled with plot details, location information (including details about Las Vegas in the Sixth World), and NPC write-ups, the book throws Shadowrun players into a cyclone of corporations, spirits, criminals, and others looking to grab a small piece of Horizon’s immense power.
The Twilight Horizon is for use with Shadowrun, Twentieth Anniversary Edition.