A Killer App Infected with a sickness that threatens to turn them into twisted sadists, the heroes travel to the city of Cuvacara on the planet Verces to find the possible origin of their affliction They soon discover that a sinister company plans to release a new social media app that will corrupt the entire city. If they can survive attacks from corporate assassins, the heroes must save the metropolis by shutting down the transmitters set to broadcast the corrupting signal. Along the way, they learn the location of the company's hidden underground base on the planet's Darkside, where a sinister executive awaits their arrival. This volume of Starfinder Adventure Path continues the Signal of Screams Adventure Path and includes: "The Penumbra Protocol," a Starfinder adventure for 9th-level characters, by Jenny Jarzabski. An exploration of the twilight-drenched city of Cuvacara on the tidally locked planet of Verces, by Jenny Jarzabski. A look at the history and motivations of the Shadow Plane outsiders known as velstracs, by Isabelle Lee. An archive of alien horrors, including a skin-harvesting, wormlike humanoid and a cruel fey exiled from the First World, by Jenny Jarzabski and James L. Sutter. Statistics and deck plans for a corporate attack vessel, by Jenny Jarzabski, plus a glimpse at a fiery planet infested with devils, by Owen K.C. Stephens. Roleplaying game adventure module exploring a haunting horror storyline.Investigate a mysterious signal and confront terrifying forces.A dark and atmospheric campaign for your Starfinder group.