From Wikipedia:
Into the Blue is a 2005 American underwater action film starring Paul Walker and Jessica Alba. It was directed by John Stockwell.
Jared (Paul Walker) and Sam (Jessica Alba) are two lovers, living a rustic life in in the Bahamas.
When Jared loses his job and friend Bryce (Scott Caan) comes for a visit, the opportunity to realize his dream arrives. Bryce, a lawyer from New York City, and his girlfriend of the week Amanda (Ashley Scott), acquired the use of a luxury vacation house and boat. Both couples take a boat trip and do some snorkeling. As they investigate the area, they come across the remains of a crashed plane containing a large quantity of cocaine. They decide not to report the crashed plane and its cargo until they have secured their claim on the sunken ship.
Jared and Bryce go to a local boat supplier. However, Jared soon finds out that Bryce, on a trip to Las Vegas, borrowed money from a loan shark. Without Jared's knowledge, Bryce and Amanda plan to retrieve some of the cocaine and sell it to local dealer/night club owner, Primo (Tyson Beckford). Primo turns out to be an associate of drug lord Reyes (James Frain) to whom the cocaine belongs. Reyes threatens Jared, Amanda and Bryce at gunpoint.
Jared is forced to retrieve the cocaine with equipment provided by Reyes. The trio breaks the bad news to Sam. He tries to convince her that it's a one-time thing, but Sam leaves him, saying that 'they' are over. Jared, Bryce, and Amanda head to sea that night after securing the gear. Before retrieving the cocaine, they decide to take advantage of the situation to uncover the site of the Zephyr. With the blower equipment, Jared is finally able to confirm the ship's identity.
Amanda is attacked by a tiger shark. She dies later in hospital. Hearing of the tragedy, Sam goes to the hospital and she and Jared are reunited. While driving back from the hospital, the threesome are confronted by Primo. A short, but intense car chase ends up with Jared leaving their truck. He surrenders to Primo and tries to get them to back off. Primo still takes him to Reyes' boat. The boat looks deserted, so Primo tells Jared to lie down on the floor of the state room. After some time, Jared goes to explore. He finds Primo, Reyes and several others shot dead in one the bedrooms. Out from the toilet emerges Bates (Josh Brolin), a local salvager and former employer of Jared's. Jared bolts from the boat and heads for shore.
Meanwhile, Sam insists on informing the police, and Bryce drops her off at her friend's home, a local cop named Roy (Dwayne Adway). He takes off to meet Jared without waiting for Sam. Roy comforts Sam and tells her he knows a guy who can help. Roy betrays Sam and takes her to Bates, who captures her.
Jared and Bryce meet up and Jared calls the captive Sam, who is handcuffed and gagged with duct tape. Bates answers her cell phone and tells Jared he will let her go immediately if Jared discloses the location of the cocaine to him. Jared refuses and insists that they meet to settle the situation once and for all.
Jared is taken aboard Bates' boat and shown the scene. The Sea Robin heads for the location where Jared directs them, but as they approach the area, they see a white substance floating on the surface. Jared tells Bates that it's half of the cocaine, ruined, and that he is about to destroy the rest. Jared jumps into the water with his hands still tied behind his back. Bates and his men change into scuba gear to go after him. Below the surface, in the plane, the divers look for Jared, who is assumed to be able to breathe to stay alive as there is trapped air in the plane. Bryce has switched places with one of the dead pilots and mount a surprise attack. An underwater struggle follows, killing all of Bates' men and wounding Bryce.
Sam frees herself with a forgotten machete, which brings one of Bates' men down into the engine room, where she locks him in. She then goes up to the bridge to call for help. The man escapes from the engine room; a chase around the boat ends in a struggle and they fall into the water. The man, wounded by Sam with a boat hook, is attacked by a tiger shark. Below, Jared and Bates are the only ones left. Jared uses an air tank as a missile by hammering off the valve. It misses Bates, but hits the fuel tank at the back of the plane, causing the entire plane to explode, killing Bates and destroying the rest of the cocaine. Sam jumps into the water, fearing for Jared's life.
This segues into a scene six weeks later, where the trio are shown to have survived and are salvaging the Zephyr. An attempt to bring a cannon up fails when the rope snaps and it sinks to the bottom. It’s a blessing in disguise as the cannon's hard landing exposes hidden gold bars. Sam and Jared are about to call it a night, but Bryce sees something in the water, and dives in on a hunch. As the scene of the boat pulls back, we hear Bryce shout that he has found the gold of Zephyr, bestowing untold wealth on the three friends.
Rated 15 certificate and not to be supplied to persons below that age.
