Its plot concerns a series of brutal murders occurring at a prestigious country club's golf course, which are apparently the work of a possessed lawn mower.

During a camping trip, two teenagers are killed by an unseen force whilst making out in a field near to the Tall Grass Country Club's famed golf course, and their mangled bodies are discovered the next morning.

Norman Osgood, the owner of Tall Grass, is determined to keep the news of the murders private as he and the rest of the club prepares for an upcoming nationally televised golf tournament.

After a young caddy becomes the latest victim, a meeting is held, and Kimmel declares the necessity of a "course-wide maniac hunt" for the killer, in which the whole club gets involved.

Roy is skeptical, however, and later that night, he and assistant professional Kelly Lange sneak into the club and cut open the bag of the lawnmower Deke was using, and discover that it contains grass and no body parts, implying that the real killer is still out there.

That night, Deke reveals that the lawnmower was once owned by his father, a former greenskeeper of Tall Grass who was decapitated by the mower in an apparent suicide the day after he was fired.