While on an assignment as a travel journalist, Pete McKell (Sam Worthington) joins a diverse group of tourists embarking on a crocodile-watching river cruise in the stunning Kakadu National Park located in Australia’s Northern Territory. The ensemble includes a passionate photographer named Simon, a local family consisting of Elizabeth, Sherry, and Allen, a couple named Gwen and Russell, as well as an American duo, Mary Ellen and Everett. Their local tour guide, Kate Ryan (Radha Mitchell), is accompanied by her loyal dog, Kevin. The cruise takes an unexpected turn following a tense encounter with two locals, Neil and Collin, leading Kate to prepare the group for their return to base.
As they journey down the river, Everett spots a distant flare, prompting Kate to investigate the potential distress signal. Upon reaching a half-sunken boat, their own vessel suddenly collides with an unseen force, causing a significant crack in the side of their boat. With limited options, Kate steers the boat towards a small island where they disembark to discuss their predicament. Tensions escalate when Everett mysteriously vanishes, having been dragged beneath the surface by an unknown predator. All signs lead to the harrowing realization that they are in the midst of a large crocodile's territory, which is known to be particularly aggressive.
As the day turns into night, the group confronts another danger: the rising tide, which threatens to engulf their island refuge. Soon, Neil and Collin return to the island, but not without disaster; the enormous crocodile attacks, demolishing their boat and leaving Collin unaccounted for. Neil suggests a daring plan to use a rope as a zip-line to the mainland, but when Mary Ellen hesitates in fear halfway across, chaos ensues. Aggression bubbles over as Allen attempts to force his way across, resulting in disastrous encounters; Neil is viciously attacked, and shortly thereafter, Allen meets a similar fate when the crocodile strikes again.
In a desperate attempt to escape, Pete devises a strategy to divert the crocodile using bait, while the group makes a break for safety. However, the plan takes a tragic turn as the crocodile seizes Kate, pulling her underwater. Pete, clutching Kevin, manages to swim to safety but soon finds himself separated from the group.
As dawn breaks, Pete pursues Kevin into a cave, where he stumbles upon the gruesome remains of Neil and, shockingly, discovers Kate—injured but alive. She has suffered severe injuries, having lost parts of her left leg and right arm. Knowing the danger is not over, Pete must tread carefully as the crocodile lingers outside the cave, feeding on Kevin. In a heart-pounding struggle, Pete engages the beast, ultimately fighting back with all his might and using the cave's environment to gain the upper hand.
Finally, Pete delivers a lethal blow to the crocodile, thus freeing both himself and the gravely injured Kate. Together, they escape the cave and return to the others waiting on the shore, as emergency paramedics arrive at the scene. As the story draws to a close, the screen fades to a newspaper article highlighting Pete's incredible bravery during this life-or-death encounter, reinforcing the harrowing yet heroic saga that unfolded in the heart of Australia’s wild.
