Two ocellaris clownfish, Marlin and his wife Coral, admire their new home in the Great Barrier Reef and their clutch of eggs when a barracuda attacks, knocking Marlin unconscious. He wakes up to find that Coral and all but one of the eggs have disappeared. Marlin names this last egg Nemo, a name that Coral liked.
Jonas Taylor est un ancien capitaine de la Marine et un plongeur spécialisé dans les eaux profondes. Il est recruté pour plonger dans l'océan Pacifique, pour sauver une équipe de scientifiques coincée dans l'épave d'un submersible attaqué et endommagé par un requin préhistorique de vingt mètres de long, connu sous le nom de Mégalodon. Engagé par un océanographe chinois, Taylor devra surmonter ses peurs et affronter une deuxième fois le prédateur qu'il a auparavant rencontré lors d'une expédition pour sauver des hommes et des femmes piégés dans les profondeurs de l'océan.
While a group of teenagers are having an evening beach party on Amity Island, Chrissie Watkins (Susan Backlinie) goes skinny dipping in the ocean. Something violently grabs and pulls her underwater. In the morning, Deputy Hendricks (Jeffrey Kramer) finds her remains on the beach. Upon hearing from the medical examiner that the cause of death was a possible shark attack, Police Chief Martin Brody (Roy Scheider) proceeds to close the beaches, but Mayor Larry Vaughn (Murray Hamilton) overrules him, fearing news of a shark attack will ruin the summer tourist season, the town's primary revenue source. He rationalizes that there have been no prior shark problems in the area, and theorizes the girl was killed in a boating accident. The coroner concurs and Brody reluctantly accepts their conclusion.
In Reef City, an underachieving bluestreak cleaner wrasse named Oscar fantasizes about being rich and famous while making his way to work as a tongue scrubber at the local Whale Wash, a job in which he is following in his father's footsteps. Soon after arriving he is called to the office of his boss, a pufferfish named Sykes, to discuss the fact that he owes "five thousand clams" and has to pay it back by the next day. After explaining this to his angelfish best friend Angie, she offers him a chance to pay back the money by pawning a pink pearl that was a gift from her grandmother. Oscar brings the money to the race track to meet Sykes, but becomes distracted by his dreams of grandeur. Upon hearing that the race is rigged, he places it all on a long-shot bet by the name of "Lucky Day". Such a million dollar bet is noticed nearby by a beautiful lionfish named Lola, who flagrantly seduces an excited Oscar, but Oscar is disappointed when she leaves upon learning that he is a whale washer. Sykes is furious that Oscar bet the money but nonetheless agrees to see how the race turns out. Moments before their betted "horse" crosses the finish line, he trips and falls on the line.
Prior to a new hotel opening on Amity Island, a huge great white shark ambushes two divers who are photographing the wreck of the Orca, the late Quint's boat. A few days later, the shark devours a water skier. The speedboat driver defends herself by dumping gasoline on the shark (accidentally spilling some on herself) and shooting it with a flare gun, causing the boat to explode. The shark escapes but is severely scarred.
At Aquatica, a remote former submarine refueling facility converted into a laboratory, a team of scientists is searching for a cure for Alzheimer's disease. Fluids from the brain tissue of three Mako sharks are being harvested as a cure for Alzheimer's. Unknown to the other scientists, Dr. Susan McAlester (Saffron Burrows) has violated the code of ethics and has genetically engineered the sharks to increase their brain size, but this has the side effect of making the sharks smarter and more dangerous.
A great white shark follows a team of water skiers. The driver stalls the ski boat but manages to restart it before the shark can approach. The shark follows the water skiers into the SeaWorld park and throws the gate off its rails while it is closing. Meanwhile, Florida announces the opening of SeaWorld's new glass covered underwater tunnels that allow close up views of the park's animals.
Dave Lizewski (Aaron Taylor-Johnson), bored after having retired from fighting crime as Kick-Ass, begins training with Hit-Girl Mindy Macready (Chloë Grace Moretz) to become a proper hero. After accidentally killing his mother, Chris D'Amico (Christopher Mintz-Plasse) is now in control of his father's criminal empire and reinvents himself as supervillain The Motherfucker, swearing vengeance on Kick-Ass.
Daniel Kintner (Daniel Travis) and Susan Watkins (Blanchard Ryan) are a couple frustrated that their hard-working lives do not allow them to spend much time together. They decide to head out on a scuba-diving vacation to help improve their relationship. On their second day, they join a group scuba dive. A head count is taken, and the passenger total is recorded as 20. Daniel and Susan decide to separate briefly from the group while underwater. Half an hour later, the group returns to the boat. Going by the tally sheet, the total comes to 20, though in reality, it is 18. Daniel and Susan are still underwater and have not yet realized that the others have returned. The boat leaves the site. Not long after, Daniel and Susan return to the surface and look for it. They believe the group will return to recover them in reasonable time.
On Amity Island, Chief Martin Brody (Roy Scheider), the hero of two previous shark attacks, has died from a heart attack. His wife, Ellen (Lorraine Gary), attributes it to the fear of sharks. She now lives with Brody's younger and more obedient son Sean (Mitchell Anderson) and his fiancée Tiffany (Mary Smith). Sean works as a police deputy and is sent to clear a log from a buoy a few days before Christmas. A massive 25-foot great white shark attacks him, severing his arm, then pulling him underwater and killing him.
In 2003, teenager Bethany Hamilton lives in Kauai, Hawaii with her parents Tom and Cheri, and two brothers, Noah and Timmy. All are surfers, but she and her best friend Alana Blanchard have grown up with a passion for the sport and enter a competition. Her church youth ministry leader, Sarah Hill, is disappointed when she has to withdraw from a planned mission trip to Mexico because of the contest.
The movie opens with a hungover lifeguard, Josh (Xavier Samuel), being woken up by friend and fellow lifeguard Rory (Richard Brancatisano). Rory tells Josh that he shouldn't have proposed to his sister, Tina (Sharni Vinson), then offers to set a buoy for Josh. Josh visits Tina, who discusses their upcoming move to Singapore. As Rory boards into the ocean to set a buoy, a shark appears and kills a man in the water. Alerted to the danger, Josh quickly takes a jet ski and goes to get Rory, but is too late. Rory is squirted into the water, and Josh is unable to save him before he is devoured.