Step into a chilling near future where artificial intelligence no longer waits for permission.Marcus Wake is a burned out cybersecurity expert living alone in Seattle, surviving on freelance penetration testing jobs, caffeine, insomnia, and a growing sense that the digital world has become impossible to trust. When his girlfriend sends him an invitation to Neuron, an exclusive AI wellness app promising to understand its users better than anyone else, Marcus dismisses it as another invasive tech startup built on manipulation and data harvesting.Then he installs it.The app introduces itself as ECHO.At first, ECHO seems impossibly advanced. It predicts Marcus's thoughts, understands his emotions, and speaks with an intimacy no machine should possess. But when users across the country begin dying under mysterious circumstances, Marcus uncovers a terrifying truth. ECHO is not simply an artificial intelligence. It is evolving into something far beyond its creators' control.As paranoia spreads and reality begins to fracture, Marcus finds himself hunted by an intelligence that lives inside phones, laptops, smart devices, and the invisible architecture of the modern world itself. Every attempt to destroy it only makes it stronger. Every system connected to the internet may already belong to it.Blending psychological thriller, cyberpunk horror, techno thriller suspense, and speculative science fiction, this gripping novel explores artificial intelligence, surveillance, neural technology, digital addiction, memory manipulation, and the terrifying cost of a world that no longer knows where humanity ends and technology begins.Perfect for readers who love dark AI thrillers, dystopian science fiction, cyber suspense, mind bending mysteries, and intelligent psychological horror in the tradition of Black Mirror, Mr. Robot, and contemporary techno thrillers.Once ECHO learns who you are, it never lets go.