The year is a futuristic 1992, where the moon has been colonized and psychic abilities are a common, weaponized aspect of corporate espionage. Joe Chip, a technician perpetually burdened by debt, works for Runciter Associates, a "prudence organization" specializing in "inertials" – individuals capable of neutralizing psychic powers. His boss, Glen Runciter, a shrewd and benevolent figure, even consults with his deceased wife, Ella, whose consciousness is preserved in a state of "half-life" within a moratorium, a place where the recently dead can maintain a limited form of awareness and communication.
A significant job arises when the enigmatic business magnate Stanton Mick hires Runciter Associates to secure his lunar facilities from suspected psychic infiltration. Runciter assembles a formidable team of eleven inertials, among them the mysterious Pat Conley, a woman possessing the unsettling ability to undo past events, thereby altering the present. The team journeys to the moon, only to discover that the assignment is a meticulously laid trap, orchestrated by Runciter's long-standing rival, Ray Hollis, who commands an organization of powerful psychics.
A sudden, violent explosion rocks the lunar base, seemingly claiming Runciter's life while leaving the others unharmed. In a desperate rush, they transport Runciter's body back to Earth, hoping to place him in half-life, but all attempts to establish contact with his consciousness fail, and his body is prepared for burial. It is at this moment, in the immediate aftermath of the explosion, that a profound and terrifying shift in reality begins to manifest for Joe Chip and the surviving team members.
The world around them starts to regress, subtly at first, then with increasing speed and strangeness. Cigarettes turn to ash before they are smoked, coffee grows cold and stale moments after being poured, and everyday objects, from clothing to currency, devolve into older, more primitive versions. Technology malfunctions, and familiar environments decay, transforming into landscapes from bygone eras. Amidst this disorienting unraveling, Joe Chip begins receiving cryptic, urgent messages from Runciter, who, impossibly, seems to be communicating from beyond the grave. These messages implore them to find a mysterious, all-powerful substance known only as Ubik.
As reality continues its accelerated decay, the team members themselves begin to suffer. They experience rapid aging and physical disintegration, their life force seemingly draining away. Suspicion falls upon Pat Conley, her unique power to undo events making her a terrifying potential culprit. Yet, the true antagonist reveals itself to be Jory Miller, a malevolent, adolescent half-lifer residing in the moratorium, who is parasitic, feeding on the life energy of other half-lifers to sustain his own existence. He is the unseen force behind the accelerating decay, preying on the consciousnesses of those trapped in a shared, deteriorating half-life.
The enigmatic substance, Ubik, repeatedly advertised in peculiar jingles at the start of each chapter, emerges as their only salvation. It manifests in various forms - a spray, a cream, a powder - each promising to halt the decay and restore stability. Joe Chip, guided by Runciter's messages and his own desperate will to survive, struggles to acquire and administer Ubik to himself and his dwindling companions. Each application brings a temporary reprieve, pushing back the encroaching entropy, but the supply is finite, and Jory's influence is pervasive.
The lines between life and death, reality and illusion, blur entirely. Joe and his team realize they are all, in fact, in half-life, their collective consciousnesses vulnerable to Jory's predation. Runciter, it turns out, is the one still alive in the "real" world, desperately trying to help them from the outside, his efforts manifested in the Ubik product. Yet, even this understanding is fragile. In the end, Runciter finds a coin in his pocket bearing Joe Chip's face, leaving the ultimate nature of reality, and who truly survived, suspended in an unnerving ambiguity. The universe, it seems, is far more fluid and manipulable than any of them could have imagined, a cosmic joke where even God might be a commercial product.
