In the heart of South Australia, brothers Reg and Lindsay Morgan run a modest yet profitable blood and bone fertiliser business. As they navigate the dusty backroads delivering goods and picking up the occasional roadkill, Reg stumbles across a tragic scene—a van wreck with its driver deceased inside. Intrigued by a blend of curiosity and a darker fascination, Reg takes it upon himself to load the body into his truck. However, this peculiar journey is soon interrupted when they encounter three stranded tourists: Sophie, James, and Wes.
Despite his initial hesitations, Reg finds himself drawn to Sophie and makes the impulsive decision to invite the trio to ride along with him. Setting off down the road, Sophie takes the front seat beside Reg, while James and Wes settle in the back, completely unaware of the grim cargo they are transporting. During the ride, a connection begins to grow between Reg and Sophie, although an undercurrent of unease begins to surface. Simultaneously, James shares his intentions of proposing to Sophie with Wes, who grapples with jealousy, fearing that his blossoming relationship might be overshadowed by this impending news.
The fateful journey takes a dark turn when the hidden body in the truck is discovered, triggering chaos and panic as Reg's nerves fray. Upon arriving at the plant, tensions flare, prompting Reg to sequester Sophie for questioning. Their brother Lindsay soon joins, demanding explanations for the frenzy. In a chilling twist, Reg proposes a horrifying method to deal with the situation: turn the tourists into fertiliser, leveraging Lindsay's expertise. Though initially horrified by this chilling idea, Lindsay’s reluctant agreement reveals their sinister past—grinding bodies for their fertiliser business after a tragic accident involving charity volunteers.
As the grim reality unfolds, the Morgans’ shocking history entwines with their current predicaments, transforming their fertiliser into a heinous symbol of humanity's depravity. Tensions mount as Wes and James are forced into a fragile alliance with Sophie, confronting the Morgans’ brutal treatment of the hapless driver. Just when the situation seems utterly hopeless, Reg experiences an unexpected bout of compassion, only to realize it may be too late for intervention.
In an audacious moment, Wes manages to escape, but his freedom stirs Lindsay’s wrath, who soon returns, dragging along the recently acquired body of a local police officer. Reg's bravado starts to falter as graphic violence unfolds around him, forcing him to grapple with the ethical implications of their actions. Their descent into moral chaos reaches an unsettling pause with the sudden appearance of Nancy, their elderly neighbor, leading to an escalating series of mistakes as Lindsay tries to silence her.
In a frantic move, Reg finds himself trapped in the trunk of a car with Wes, who is desperately seeking his severed hand. As they strain against their bindings, Reg overhears Lindsay spinning a tale about his supposed departure from the area, filling him with resentment and igniting a plan to steal Lindsay's keys under the guise of distraction. Just as the moment approaches, Wes’s frantic quest leads to chaos, prompting Lindsay to unleash an unrelenting attack on both Wes and Nancy.
Amidst the cacophony, Reg seizes the moment to make his escape with the pilfered keys. The panic escalates as James and Sophie are initially frozen in fear by the gunshots echoing through the air, but they soon realize that inaction is insufficient. Sophie ultimately decides to abandon them, leaving James grappling with rejection just as the violence intensifies.
In a bold twist of fate, Reg enacts his revenge, clutching Lindsay and pulling him into the very grinder they once used for their grotesque dealings. The tension dissipates for a brief moment as Reg and Sophie share a fleeting spark of attraction before their paths diverge.
In a chilling post-credits reveal, James, consumed by despair, recklessly sprints into the street, only to be struck down by an unthinking driver, sealing the film's message of chaos and consequence in the most brutal of ways.
