Plot

Three friends filming an audition tape for an extreme reality-TV show find themselves stranded in shark-infested waters, turning their recording into a bloody diary of death. Do they have what it takes to survive the open water?

To capture thrilling, face-to-face encounters with deadly great white sharks, the young thrill-seekers, Josh; his half-brother, Jeff, and Jeff's girlfriend, Megan, set off to the vast and unforgiving Australian coast to go cage-diving. As the audacious friends start filming an audition tape for an extreme reality-TV show in the relative safety of their heavy cage, a towering wave capsizes their small boat, stranding the reckless trio in the cold water. Now, as the day grows dim, and raw fear gets the best of the defenceless trio, a famished school of man-eating oceanic predators start closing in on them, turning their recording into a bloody diary of death. Do they have what it takes to survive the open water?—Nick Riganas

The film begins with a warning that "In 2015, an Underwater camera was found at the bottom of the ocean. We would like to warn viewers that the footage on the camera contains graphic material." setting up the film as a Found-Footage Documentary.

A news segment is running a story on a Cage Diving company that had a boat capsize due to a giant wave. There are still missing people, including 3 friends who had all gone together. 1 Week after the newscast, a shattered and broken camera is found with the SD Card to be intact. An interview with the diver who found the camera explains he uploaded some of the footage off of the SD Card to social media pages in the hopes to inform the owners their camera was found. The rest of the footage is shown and the story of the missing 3 friends is told...

In Laguna Beach, California, brothers Josh and Jeff alongside Jeff's girlfriend, Megan, are preparing to audition for a new reality game show that offers contestants to win $100,000. Part of their audition tape has to include proof of the applicant's physical and mental strength. So they thought the best video to make was Cage Diving in the Shark Cage Dive Tour. Jeff buys an Underwater camera to film their audition tape, and attempts to record Megan getting in the shower, but the battery dies.

After a full night's charge, Jeff begins to record their audition tape with their introductions. They continue to record random footage for themselves, including Jeff taking medications. Jeff is against recording every little detail at first, especially because the contest is not open to people with medical conditions. However, they continue to record their nights out on town, dinner, and Jeff even attempts to record himself having sex with Megan, to which Megan turns the camera off once again.

3 days before their cage dive, Josh, Jeff, and Megan fly to Sydney, Australia where they meet up with Josh and Jeff's cousin, Greg. There, they spend time together on the beach and out on the ocean, allowing the family to reconnect after spending so many years apart. On the final night at Greg's, Greg throws a "good luck" party for Josh, Jeff, and Megan. Jeff then records a a confession in a bedroom by himself to the camera that he plans on proposing to Megan on the show. In the middle of the recording, Megan knocks on the door to inform Jeff that their mother has called and is waiting on the line downstairs. Jeff quickly throws a T-Shirt over the camera and runs downstairs to take the call, but the camera continues to record. Megan stays in the room and is met by Josh, and then they begin to kiss, showing they are having an affair behind Jeff's back.

1 day before their cage dive, the trio leave Sydney and fly to Adelaide, Australia where the Shark Cage Dive Tour is held. They arrive at their Hotel where they go for a swim at the end of the day before going to bed to get ready for the Tour. After their swim, Jeff shows Josh the footage of his proposal on their computer while Megan is away. Jeff realizes the camera kept recording and before Jeff sees the footage of Josh and Megan kissing, Josh pulls him away from the computer and continues to distract Jeff until the footage is over.

The next day, they all head off to the docks for their tour. After some safety instructions, the boat heads out into the water. As the boat is sailing out, they watch a video on the boat about how to Survive A Shark Attack, but Megan is not worried even when Josh is signing a Life Waiver as she points out the large steel cage that they'll be in. After the boat stops at the dive location, another instructor goes over their safety vest information while other crew members begin to attract the sharks with bait. Several tourists are shown entering and leaving the cage, where one person had to leave early due to having a panic attack. Josh, Jeff, and Megan finally enter the cage themselves showing their time underwater where the cage is attacked several times by the Great White's that are circling the boat.

Just as they were resurfacing, a giant wave capsizes the boat tipping everyone on-board into the ocean. All 3 of them are able to exit the cage and head back to the surface to meet up with the other survivors, but the sharks are still present. The find they are near a woman who is holding an unconscious man that is bleeding to death from a large open wound on the side of his face. The blood attracts the sharks and the man and woman are killed.

Josh, Jeff, and Megan begin to swim away where they see another survivor waving for them. They all begin to swim towards one another but the other person is then killed by sharks too, leaving Josh, Jeff, and Megan by themselves. They begin to wade water until help arrives and Megan realizes she has a cut on her leg. A yacht is sailing nearby and Josh begins to swim for it to get rescued, but Megan prevents him from doing so saying they need to stick together. After a short while, they even hear a helicopter nearby but are distracted by Megan as she says she felt something near her feet. They pull up some of the bait used to attract the sharks and throw it just in time as a shark eats the bait and swims off. Still waiting on rescue, their only saving grace is a single life vest that floats to the surface. Later on, a cooler begins to float a bit further away, and Jeff was going to retrieve it with the hopes of giving them supplies, but the cooler is attacked by more sharks.

Night falls upon them and they are still stranded out in the water. But to everyone's delight, they find a life raft where they are supplied with food, first aid, and a couple of flares. Megan fires the first flare in the hopes this will lead to their rescue. While they wait, they fall asleep but are quickly awoken as the raft bumps into another tourist that was floating in the ocean. They pull the tourist into the raft and discover she is still alive but very cold. Megan has the idea of using the second flare to fire another signal and then use the stick as a heat source to warm her up, but Jeff and Josh disagree. Megan persists this will be the best option and Josh and Jeff start to struggle with her to take away the flare. The flare is then fired inside the life raft and the woman they pulled in is burned alive. Now they are left stranded in the ocean once again.

It is still nighttime and Josh and Megan begin to argue where Josh accuses Megan of being a liar. The affair is then revealed to Jeff. Their argument is interrupted as sharks have returned due to Megan's leg injury from earlier. She is then pulled underneath the water and is killed by the sharks.

The next morning, Josh and Jeff begin to fight and argue over the affair and Megan's death, but Jeff passes out due to not having taken his medications, which is shown to have been for his heart. With little battery left, the footage cuts to Josh recording by himself in his own confession, implying Jeff's body was let go and he is dead. Josh records an apology to Jeff and Megan and a farewell to his family. While recording, a helicopter begins to fly by and Josh frantically begins yelling to the helicopter to be rescued. But before he could be found, a shark swims up and bites Josh, killing him too, and crushing the camera.