At its core, the story follows a real - estate agent whose job takes a terrifying turn when they specialize in selling haunted houses. In this shadowy universe, any dwelling marred by an unnatural death is labeled a “haunted house,” split into two categories: “green haunted houses,” where occupants may remain unharmed, and “red haunted houses,” which promise certain doom to anyone who crosses their threshold. A single ill-fated sale of a red haunted house catapults the agent into a nightmarish spiral of encounters with the supernatural.

The narrative is a masterclass in suspense, filled with hair - raising scenarios. During property viewings, the agent often finds themselves alone with malevolent entities lurking just out of sight. Once, while showing a decrepit mansion, the temperature plummeted, and a trail of black slime oozed down the walls, forming grotesque symbols that seemed to taunt them. Another time, the agent was trapped in a seemingly endless maze of rooms within a haunted townhouse; each door led to another identical chamber, and the only sound was the echoing laughter of an unseen presence.

As the story progresses, the agent discovers that the spirits haunting these houses aren't just aimless phantoms. Some seek revenge against those who wronged them in life, while others are trapped in a loop of their own tragic deaths, forcing the agent to solve their mysteries to escape. In one particularly harrowing case, a red haunted house was home to the spirit of a woman who was buried alive. Her ghost would appear every night, dragging her bloodied hands across the floorboards, leaving behind a trail of decay. To break the curse, the agent had to uncover the identity of her killer hidden in the house's forgotten history.

The plot seamlessly weaves the mundane tasks of real - estate work—negotiating contracts, staging properties—with the surreal horror of the paranormal. The agent must navigate not only vengeful ghosts but also the sinister schemes of rival agents who are willing to exploit the supernatural for profit. One antagonist even goes so far as to release a malevolent spirit from a red haunted house into a competitor's listing, turning it into a death trap to drive down prices and monopolize the market.

As the agent delves deeper into the haunted real estate underworld, they uncover a larger conspiracy that threatens to unleash a horde of ancient, powerful entities. Each haunted house is a piece of a terrifying puzzle, and solving it means confronting their own darkest fears. With heart - pounding twists and an ever - escalating sense of dread, Thriller: I Only Sell Haunted Houses keeps readers on the edge of their seats, questioning every creak in the floorboards and shadow in the corner.