We fade on a National Geographic-style documentary about how misunderstood sharks are. Abruptly, after about 2 minutes, the film simply cuts off to static, and we pull back to see it was on a TV, sitting in a boardroom with Meryl Streep's character, Lisa Nielsen, at the head of the table. Nielsen says that this is rough footage they've put together, but that they need funding in order to finish their film. She introduces the crew she's put together to the board. To her immediate right is William Caulson(Liam Neeson), considered to be one of the world's foremost experts on shark observation. He will be doing the actual diving for the expedition. Next to him is Michael Griegson (William H. Macy). He is a conservationist, who will be taking a leave of absence from his job as a lobbyist for the Clean Sea Federation in order to consult and provide narration. Finally, she introduces the two people to her left. Eric Henry(Thomas Jane) and John Liason(Matt Keeslar) are considered two of the finest technical support people for underwater photography in all of the world. After she introduces the team, the board agrees to fund the project.

Credits roll over a scene of the crew's large boat out at sea with a title card a la X-Files in the corner. "Southern Atlantic Ocean, 100 miles off the coast of Brazil." We gradually pull in to the boat, where the crew is goofing off, watching satellite cable, and relaxing, except for Caulson, who is intently watching a sonar screen. Suddenly, we hear a series of sounds from the sonar. "We got a group!," Caulson says. The crew springs into action, stopping the boat quickly. Neilsen begins to bark orders and they prepare to dive. Caulson and Henry both suit up in diving gear and get into shark cages, which they lower into the water. In addition to all of his other gear, Henry is carrying a large underwater video camera.

As they lower the two men into the sea, Liason is bent over a video console, watching the images sent up from the camera and fiddling with knobs to focus them. The cages drop, and they are surrounded by sharks. Filming continues for a while, until a small boat sails across the sea to right near the diving area and stops. The crew attempts to hail it, but they get no response. Silently, Kiefer Sutherland's character, William Harriman, steps out onto the other boat's deck and raises his arm over the water. It is caked with scars, from deep cuts. In a flash, and with no warning, he pulls a huge knife from his boot and slices his arm wide open, allowing the blood to spill into the sea. Immediately, he grabs a rag, and covers the wound. We see the blood coming down from the perspective of Caulson, in the shark cage, and as the blood comes down, the sharks go into a frenzy, pounding against the cage with increasing fury. Caulson and Henry are both screaming over the headset, demanding that the crew lift them up, and the crew moves as quickly as possible.

In a panic, they begin the process of getting the cages out of the water, but not until Dr. Marcus Narg (Scott Glenn's character) and Ivan Gelicovich (Oldman's character) step out of the other boat and begin firing harpoons and spear guns into the water. We see the shots into the water from behind the harpoons and spears, and watch the weapons streak through the water, brutally killing one shark. One of the spears gets stuck in the bars of Henry's cage, and its tether back to the spear gun snaps. The crew pulls both of the cages out of the water, and then inspects the weapon stuck in the one cage. Greigson runs the tip over his hand, just grazing it, but it cuts. "These are damn sharp," he says. "I'm afraid we're in for some serious trouble."

We cut to the crew discussing what their next action will be and they agree to try and hail the hunters' ship. Griegson gets on the radio and attempts to hail the hunters. We cut to the hunters' boat, where Gelicovich is sitting at the radio, listening, and Naig, a doctor, is sewing up the large cut on Harriman's arm. Gelicovich responds to the transmission coldly--"These are our sharks. Leave now, or we will be forced to do to you what we are trying to do to them." He then flips off the radio.

The radio message distresses the crew of the documentary, particularly Henry and Liason, who want to get out of there. Greigson, on the other hand, passionately argues for staying. These sharks are on the international protected species list. Hunting them is not merely dangerous, but illegal. The crew has a social responsibility to protect the sharks. The crew argues, with Caulson quickly taking Greigson's side, and Nielsen staying silent. After about 5 minutes, Nielsen calls for silence. "I am the director of this film. We promised our backers a good film, and we're going to deliver. We're staying, and that's final."

Late that night, on board the ship we hear an inhuman moaning from outside the ship. The hunters have speared another shark, and are attempting to haul it in. Griegson is awakened by the sounds and steps out on to the deck, where he cries and begins to pace. The sharks become more aggressive every time the hunters kill one, hitting both boats with increasing force, and awakening the entire documentary crew from their rest.

Cut to early the next morning. The crew of the documentary is gathered within their boat, and Griegson is hunched over a laptop computer. He beckons the rest of the crew to come over. On the screen is a picture of Harriman and a dossier. Griegson summarizes the information on the screen: His name was William Harriman, and he was a billionaire hunter and financier, last seen on an African Safari. There, he proclaimed that none of the game in that part of Africa was dangerous enough for him--he wanted to hunt something else--a predator that he saw as more deadly than the lion, and he was going to hunt it his way. He left the safari's camp alone one night, and hadn't been seen since. Caulson asks if they have anything on the other two. Griegson pushes some buttons and says that there is. Dr. Narg's picture flashes up on screen. Griegson again summarizes the dossier for the others: Dr. Marcus Narg, Harvard Medical School grad, who soon became known as a person who criminals could go to, no questions asked, for medical care. He disappeared about 6 months after Harriman did, just before an indictment of him was scheduled to be released. "And the third one?" asks Nielsen. More buttons are pushed. "Yep. Ivan Gelicovich. Russian, known for providing equipment and supplies, and an amateur hunter himself. Said that if there was one thing he could take out, it was a shark."

Liason is clearly scared. "We can't take on these people. They know how to kill. They've got guns. What do we have?" Neilsen smiles and pauses. "We have you." Liason looks dumbfounded, and Neilsen responds, with a knowing smile. "Can you hook up the satellite dish so it can transmit as well as recieve?" "You bet!," he says, "but it'll take a while." "That's fine. I have a plan."