On a Vista Airlines flight from LAX to Los Cabos, the plane crashes into the Pacific Ocean after hitting birds, killing both pilots and several passengers. The remaining survivors, including Ava, her boyfriend Jed, Jed’s friend Kyle, young girl Rosa and her grandmother Mardy, Ava’s bodyguard Brandon, and flight attendant Danilo, find themselves trapped in an air pocket at the rear of the fuselage as it sinks underwater.
Brandon initially takes charge, but a tiger shark attacks and drags him away when he tries to retrieve an oxygen tank. Mardy, a former army nurse, treats Kyle’s injured arm, while the survivors argue about their next course of action, knowing they only have a few hours of air left. Suddenly, the wreckage slides down a rock face, dragging them deeper into the ocean and precariously resting on the edge of a cliff.
The survivors decide to leave the aircraft and swim to the surface, reasoning that air bubbles from their inflatable life vests can scare the sharks away. They search for diving gear, and a rescue helicopter spots debris from the plane, sending divers to investigate. The divers are attacked by the shark, with one being dragged off and the other going missing.
The survivors are again attacked by the shark, which bites off Jed’s leg. He goes into shock and dies. Ava retrieves scuba gear, and the survivors prepare to swim to the surface. Kyle, afraid to swim due to a childhood trauma, is eventually convinced to leave with the group. The damaged cockpit breaks off and falls into the abyss, and Mardy decides to stay behind, asking Ava to look after Rosa.
As they swim through the fuselage to the exit, Ava uses bubbles from her life vest to deter the shark. Kyle is attacked by the shark, allowing the others to escape. They find the missing diver’s oxygen tank and use it. Ava gives the tanks to Danilo and Rosa, and they float to the surface while she narrowly escapes the shark and sinking wreckage.
Ava miraculously reaches the surface but finds no other survivors except for Rosa’s stuffed animal. The rescue helicopter picks her up, reuniting her with Danilo and Rosa. Rosa asks about her grandmother, but Ava can only embrace her, and they cry together. Rosa throws her stuffed animal into the ocean as a tribute to the dead as the helicopter flies to safety.