During a brutal rainstorm in the Northern Territory, a trio of poachers head out onto a swollen river to hunt crocodiles. They spot a colossal saltwater crocodile, about 7.6 metres long, and move in to capture it. The beast claws at the boat, overturning it and unleashing a fatal assault that leaves only one survivor—John Besser [Max Phipps].
The next day, a rescue party forms: ranger and herpetologist Steve Harris [John Jarratt], Oondabund [Burnham Burnham], the respected leader of a local Aboriginal community, and his second-in-command Adjaral [David Gulpilil]. They set out to check on the poachers and pull Besser from danger. Besser, shaken but unbroken, swears vengeance against the creature that ruined his life.
Tension mounts when the monster cruelly takes the life of an Aboriginal child, intensifying the community’s fear and anger. Harris is given a dangerous mission by his superior Rex Garret [Ray Meagher]: kill the beast. But Oondabund refuses to sanction such violence, insisting that Numunwari—the beast’s name—is believed to be a sacred repository of the community’s souls. The conflict between a hunter’s duty and spiritual law deepens the stakes.
The creature resurfaces by a harbor, killing a thug and pushing Harris to act. Harris, however, is determined to end the threat without needless bloodshed and proposes a plan: hunt Numunwari, capture it, and release it downstream away from people—an option Garret reluctantly accepts. The hunt changes from order to necessity as the river becomes a corridor of danger and demand.
Harris, Oondabund, and Adjaral pursue the beast along the winding river. Meanwhile, Besser and a friend hustle to trap it with a net, driven by vengeance as much as fear. In a brutal clash, Numunwari drags Besser into the water and bites off his arm, a savage reminder of the predator’s power.
With the beast finally captured and brought onto land, the trio load it into a truck and push upriver, unaware that Besser and his allies—and Cathy Pope [Nikki Coghill], Harris’s girlfriend—are closing in, hoping to warn them. They reach the beast’s home base just as Besser and his party arrive, sparking a violent confrontation. Besser drives in with an axe while his companions engage Harris, Oondabund, Cathy Pope, and Adjaral in a gunfight. Oondabund is fatally wounded, and the defense holds long enough for the others to keep the beast at bay.
In the end, Numunwari’s hunt culminates in tragedy for Besser, who is dragged underwater by the creature, leaving his fate sealed. Sometime after, Adjaral performs a stark ritual, feeding Oondabund’s remains to the beast in accordance with their religious beliefs, a final, somber note in a tale where nature, culture, and vengeance collide on the river.
