The film begins with Jess, a young blonde woman, as she joyfully wanders in the water, only to suddenly feel an unsettling presence around her. Her boyfriend, Keith grabs her playfully and hoists her onto his shoulders, prompting a flurry of affection. Despite her teasing protests, he flings her top away, insisting he’ll simply get some food. As he retreats to their trailer, Jess reclaims her top, but her tranquility is shattered when she suddenly feels a violent tug in the water. A shark attacks her, pulling her deep underwater as her desperate screams go unheard—an oblivious Keith is entirely unaware of the horror unfolding beneath him.
Meanwhile, we transition to a group of seven university students from Tulane, comprising Sara (played by Sara Paxton), Nick, Beth, Malik, Maya, Blake, and Gordon, who journey to Sara's family vacation house near the secluded Lake Pontchartrain. At a local bait shop, a chance encounter with Dennis, Sara's old flame, and his friend Red leads to a tense moment as they hurl racially charged insults at Malik and his fiancée, Maya. Sara steps in to defuse the situation. As they set off in a speedboat towards the vacation home, they attract the attention of Sheriff Sabin, who initially appears stern but soon surprises them by joining in for a beer, expressing his joy at Sara’s return after three years.
The atmosphere turned playful as Gordon tries to charm Beth while Sara soaks up the sun. However, the fun is quickly interrupted—the water-skiing adventure takes a dark turn when a shark targets Malik. Despite desperate attempts from Nick, Blake, and Maya to rescue him, Malik ends up returning to the shore, severely injured and missing an arm. Nick, using his medical training, provides immediate help, but their hopes are dashed when blood from Malik’s wound draws in more danger—a shark assaults their boat, causing chaos that results in Maya being thrown overboard and consumed.
The boat ultimately crashes, leaving Sara, Nick, and Malik stranded on the shore without a way to call for help due to lack of cell service and landlines. Tensions escalate as Dennis and Red show up again, proposing to ferry Beth and Gordon to safety. Nick, however, stands firm on keeping Malik from leaving. During the boat ride, Red suggests a storm may have allowed sharks into the lake, but he ominously hints that they were released on purpose. The sinister plot unravels when Dennis brazenly confesses their darker motives—he and Red have been luring and feeding young college students to the sharks for entertainment.
As chaos unfolds, Beth finds herself sacrificed to cookie cutter sharks, while Gordon narrowly escapes the same fate. In a desperate effort to retaliate after learning of Maya’s fate, Malik arms himself and fights off a hammerhead shark, but is only further wounded. He makes the ultimate sacrifice, allowing Blake to escape on a jet ski, yet Blake is also fatally claimed by a massive great white shark.
In a tense climax, Sheriff Sabin builds suspense by offering Sara and Nick some soup, but as Nick loses consciousness, Sara discovers a dark truth about Sabin's intentions. When he reveals his plan to film their gruesome ends for viral thrills, chaos ensues. Nick manages to break free, igniting an explosion that leaves Sabin at the mercy of sand tiger sharks. Dennis's vengeance against Sara comes to a head when he lowers her into a shark cage. As danger surrounds them, Nick surfaces, and a struggle between him and Dennis culminates in Dennis being devoured by the lurking great white.
Rescue becomes a race against time as Nick uses a powerhead provided by her dog to save Sara from the cage. After a desperate struggle, they manage to escape and Nick performs CPR to revive her. As they share a moment of relief and gratitude, the film crescendos with an ominous final shot of a breaching great white shark, hinting at the continuing peril lurking in the depths.
