On vacation, Grace, her husband Adam, and Grace's younger sister Lee decide to attend a crocodile show, drawn by the thrill of watching predators up close and the promise of a break from routine. The following day, Grace discovers she is pregnant but keeps the news from Adam, adding a subtle edge of secrecy to the trip. Theyenk up a spontaneous fishing excursion with Black Water Barry's, hoping a boat ride into the mangrove swamp will yield some catches and quiet excitement.
At the docks, Barry isn’t available, so another guide, Jim, steps in, armed with a revolver and a pragmatic, no-nonsense demeanor. They set off with a cautious sense of adventure, aiming for the usual spots where fish are expected to bite. After failing to snag any fish on the familiar route, Jim proposes venturing deeper into the swamp, chasing a chance to test their luck in a more challenging waterway. In a small clearing, Lee spots something through her camera and alerts Grace, but the moment proves fleeting and they find nothing out of the ordinary.
Then disaster strikes: the boat capsizes, plunging everyone into the murky water. Jim is killed underwater, and Adam quickly realizes a crocodile has attacked them. He helps Grace onto a nearby tree and scans the water, searching for Lee, who becomes tangled beneath the wreckage. Grace sees the beast lurking nearby and convinces Adam to return to look for Lee. Lee frees herself, but the crocodile closes in, pursuing her as she clings to the overturned boat. The beast thrashes the vessel in an attempt to throw her off, triggering a tense struggle. Adam and Grace distract the predator just long enough for Lee to scramble to safety, and the animal retreats.
Desperate to save Lee, they try to use the boat’s ropes to haul her to safety, but the boat gets jammed and stuck in the murky water. Lee, hesitant and terrified, must swim the dangerous distance to reach safety, making it to the other side with panic flaring mid-swim. The two women consider waiting for help, but Grace’s momentary thoughts of rescue are interrupted when Adam declares that no one saw them leave, prompting Grace to climb back up toward the mainland. She is forced to retreat after discovering remnants of a corpse, a stark reminder of the danger surrounding them. An impatient Adam wades toward the boat, overturns it, and pays with his life as the beast closes in. The two women cling to their plan, only to be thwarted again as the boat drifts away, leaving them stranded. That night, the crocodile feeds on Adam, and the camp is haunted by the predator’s ominous presence.
The next day brings a new, brutal realization: they must press forward to survive. The beast again confronts them, driving them back to their original tree, and Grace endures a nasty thigh bite that bleeds heavily, deteriorating her condition with each passing hour. A passing boat finally appears, but its propeller drowns out their desperate shouts for help. Lee makes another determined bid to reach the boat and succeeds, only for the crocodile to lunge into the craft. Lee flings herself onto a very small island alongside Jim’s body, patches herself up, and retrieves Jim’s revolver, only to find it jammed with mud. She clears the jam and gears up for a final stand.
In a tense confrontation, she uses Jim’s detached arm as a grim lure to draw the creature closer, gripping the pistol ready to fire. The beast attacks, but the gun jams again. She flees with the predator close behind, and when she stops to gain a moment’s breath, the crocodile makes a fatal lunge. This time the weapon finally cooperates, and Lee manages to shoot and kill the animal, ending the immediate threat. With the danger gone, she returns to Grace, who has died from her injuries. Grief-stricken, Lee mourns as she places Grace on the boat and paddles away from the mangrove, the ghostly silence of the swamp weighing heavily on her.
